Rules for Classification and Construction

I Ship Technology
1 Seagoing Ships

1 Hull Structures

This edition is for information only. It includes reference links between the 2012 and 2013 editions.

Edition 2012
 The following Rules come into force on 1 May 2012.

Alterations to the preceding Edition are marked by beams at the text margin.

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Germanischer Lloyd SE.

Published by: Germanischer Lloyd SE, Hamburg

 Table of Contents

Section 1 General, Definitions .......................................................................................................1-1

A. Validity, Equivalence ............................................................................................................... 1-1
B. Restricted Service Areas........................................................................................................... 1-2
C. Ships for Special Services ........................................................................................................ 1-2
D. Accessibility ............................................................................................................................. 1-2
E. Stability .................................................................................................................................... 1-2
F. Vibrations and Noise ................................................................................................................ 1-3
G. Documents for Approval .......................................................................................................... 1-3
H. Definitions ................................................................................................................................ 1-5
J. International Conventions and Codes ....................................................................................... 1-7
K. Rounding-Off Tolerances ......................................................................................................... 1-7
L. Regulations of National Administrations.................................................................................. 1-8
M. Computer Programs.................................................................................................................. 1-8
N. Workmanship ........................................................................................................................... 1-9

Section 2 Materials.........................................................................................................................2-1
A. General ..................................................................................................................................... 2-1
B. Hull Structural Steel for Plates and Sections ............................................................................ 2-1
C. Forged Steel and Cast Steel...................................................................................................... 2-6
D. Aluminium Alloys .................................................................................................................... 2-6
E. Austenitic Steels ....................................................................................................................... 2-7

Section 3 Design Principles............................................................................................................3-1

A. General ..................................................................................................................................... 3-1
B. Upper and Lower Hull Flange .................................................................................................. 3-2
C. Unsupported Span .................................................................................................................... 3-2
D. End Attachments ...................................................................................................................... 3-4
E. Effective Breadth of Plating ..................................................................................................... 3-5
F. Proof of Buckling Strength....................................................................................................... 3-5
G. Rigidity of Transverses and Girders ....................................................................................... 3-15
H. Structural Details.................................................................................................................... 3-15
J. Evaluation of Notch Stress ..................................................................................................... 3-18
K. Corrosion Additions ............................................................................................................... 3-20
L. Additional Stresses in Asymmetric Sections/Profiles............................................................. 3-21
M. Testing of Watertight and Weathertight Compartments ......................................................... 3-21

Section 4 Design Loads ..................................................................................................................4-1

A. General, Definitions ................................................................................................................. 4-1
B. External Sea Loads................................................................................................................... 4-2
C. Cargo Loads, Load on Accommodation Decks ........................................................................ 4-4
D. Loads on Tank Structures......................................................................................................... 4-5
E. Design Values of Acceleration Components ............................................................................ 4-7
Section 5 Longitudinal Strength ................................................................................................... 5-1
A. General..................................................................................................................................... 5-1
B. Loads on the Ship's Hull .......................................................................................................... 5-6
C. Section Moduli, Moments of Inertia, Shear and Buckling Strength......................................... 5-9
D. Design Stresses ...................................................................................................................... 5-15
E. Permissible Still Water Loads................................................................................................ 5-19
F. Guidance Values for Large Deck Openings ........................................................................... 5-20
G. Bulk Carriers.......................................................................................................................... 5-21

Section 6 Shell Structures.............................................................................................................. 6-1

A. General, Definitions ................................................................................................................. 6-1
B. Bottom Plating ......................................................................................................................... 6-1
C. Side Shell Plating ..................................................................................................................... 6-3
D. Side Plating of Superstructures ................................................................................................ 6-4
E. Strengthening of Bottom Forward............................................................................................ 6-4
F. Strengthenings in Way of Propellers and Propeller Shaft Brackets, Bilge Keels..................... 6-5
G. Openings in the Shell Plating ................................................................................................... 6-6
H. Bow Doors and Inner Doors .................................................................................................... 6-6
J. Side Shell Doors and Stern Doors.......................................................................................... 6-13
K. Bulwark.................................................................................................................................. 6-15

Section 7 Decks............................................................................................................................... 7-1

A. Strength Deck........................................................................................................................... 7-1
B. Lower Decks ............................................................................................................................ 7-5
C. Helicopter Decks...................................................................................................................... 7-6

Section 8 Bottom Structures.......................................................................................................... 8-1

A. Single Bottom .......................................................................................................................... 8-1
B. Double Bottom......................................................................................................................... 8-2
C. Bottom Structure in Machinery Spaces in Way of the Main Propulsion Plant......................... 8-8
D. Transverse Thrusters .............................................................................................................. 8-10
E. Docking Calculation............................................................................................................... 8-12

Section 9 Framing System ............................................................................................................. 9-1

A. Transverse Framing.................................................................................................................. 9-1
B. Bottom-, Side- and Deck Longitudinals, Side Transverses ...................................................... 9-5

Section 10 Deck Beams and Supporting Deck Structures .......................................................... 10-1

A. General................................................................................................................................... 10-1
B. Deck Beams and Girders........................................................................................................ 10-1
C. Pillars ..................................................................................................................................... 10-3
D. Cantilevers ............................................................................................................................. 10-3
E. Hatchway Girders and Girders Forming Part of the Longitudinal Hull Structure .................. 10-4
Section 11 Watertight Bulkheads..................................................................................................11-1
A. General ................................................................................................................................... 11-1
B. Scantlings ............................................................................................................................... 11-3
C. Shaft Tunnels.......................................................................................................................... 11-6

Section 12 Tank Structures ...........................................................................................................12-1

A. General ................................................................................................................................... 12-1
B. Scantlings ............................................................................................................................... 12-3
C. Tanks with Large Lengths or Breadths................................................................................... 12-7
D. Vegetable Oil Tanks............................................................................................................... 12-7
E. Detached Tanks ...................................................................................................................... 12-8
F. Potable Water Tanks .............................................................................................................. 12-8
G. Swash Bulkheads.................................................................................................................... 12-8

Section 13 Stem and Sternframe Structures ................................................................................13-1

A. Definitions .............................................................................................................................. 13-1
B. Stem........................................................................................................................................ 13-1
C. Sternframe .............................................................................................................................. 13-1
D. Propeller Brackets .................................................................................................................. 13-5
E. Elastic Stern Tube .................................................................................................................. 13-5

Section 14 Rudder and Manoeuvring Arrangement ...................................................................14-1

A. General ................................................................................................................................... 14-1
B. Rudder Force and Torque....................................................................................................... 14-3
C. Scantlings of the Rudder Stock............................................................................................... 14-4
D. Rudder Couplings................................................................................................................... 14-9
E. Rudder Body, Rudder Bearings............................................................................................ 14-12
F. Design Yield Moment of Rudder Stock ............................................................................... 14-15
G. Stopper, Locking Device ...................................................................................................... 14-15
H. Propeller Nozzles ................................................................................................................. 14-16
I. Devices for Improving Propulsion Efficiency ........................................................................ 14-16
J. Fin Stabilizers....................................................................................................................... 14-17

Section 15 Strengthening for Navigation in Ice ...........................................................................15-1

A. General ................................................................................................................................... 15-1
B. Requirements for the Notations E1 - E4................................................................................. 15-6
C. Requirements for the Notation E .......................................................................................... 15-12

Section 16 Superstructures and Deckhouses................................................................................16-1

A. General ................................................................................................................................... 16-1
B. Side Plating and Decks of Non-Effective Superstructures ..................................................... 16-2
C. Superstructure End Bulkheads and Deckhouse Walls ............................................................ 16-3
D. Decks of Short Deckhouses.................................................................................................... 16-5
E. Elastic Mounting of Deckhouses ............................................................................................ 16-5
 F. Breakwater ............................................................................................................................. 16-8

Section 17 Hatchways .................................................................................................................... 17-1

A. General................................................................................................................................... 17-1
B. Hatch Covers.......................................................................................................................... 17-2
C. Hatch Coamings and Girders ............................................................................................... 17-12
D. Smaller Openings and Hatches............................................................................................. 17-14
E. Engine and Boiler Room Hatchways ................................................................................... 17-17

Section 18 Equipment .................................................................................................................... 18-1

A. General................................................................................................................................... 18-1
B. Equipment numeral ................................................................................................................ 18-2
C. Anchors .................................................................................................................................. 18-2
D. Chain Cables .......................................................................................................................... 18-4
E. Chain Locker.......................................................................................................................... 18-4
F. Mooring Equipment .............................................................................................................. 18-5
G. Towing Equipment................................................................................................................. 18-7
H. Towing and Mooring Arrangement Plan................................................................................ 18-8

Section 19 Welded Joints............................................................................................................... 19-1

A. General................................................................................................................................... 19-1
B. Design .................................................................................................................................... 19-2
C. Stress Analysis ..................................................................................................................... 19-10

Section 20 Fatigue Strength .......................................................................................................... 20-1

A. General................................................................................................................................... 20-1
B. Fatigue Strength Analysis for Free Plate Edges and for Welded Joints Using Detail
Classification.......................................................................................................................... 20-4
C. Fatigue Strength Analysis for Welded Joints Based on Local Stresses.................................. 20-8

Section 21 Hull Outfit .................................................................................................................... 21-1

A. Partition Bulkheads ................................................................................................................ 21-1
B. Ceiling.................................................................................................................................... 21-1
C. Side Scuttles, Windows and Skylights ................................................................................... 21-2
D. Scuppers, Sanitary Discharges and Freeing Ports .................................................................. 21-4
E. Air Pipes, Overflow Pipes, Sounding Pipes ........................................................................... 21-5
F. Ventilators.............................................................................................................................. 21-8
G. Stowage of Containers ........................................................................................................... 21-9
H. Lashing Arrangements ......................................................................................................... 21-10
J. Car Decks............................................................................................................................. 21-10
K. Life Saving Appliances ........................................................................................................ 21-11
L. Signal and Radar Masts........................................................................................................ 21-11
M. Loading and Lifting Gear..................................................................................................... 21-13
N. Access to the Cargo Area of Oil Tankers and Bulk Carriers................................................ 21-13
O. Guard-Rails .......................................................................................................................... 21-21
 P. Accesses to Ships ................................................................................................................. 21-21

Section 22 Structural Fire Protection...........................................................................................22-1

A. General ................................................................................................................................... 22-1
B. Passenger Ships carrying more than 36 Passengers................................................................ 22-1
C. Passenger Ships carrying not more than 36 Passengers........................................................ 22-17
D. Passenger Ships with 3 or more Main Vertical Zones or with a Load Line Length of 120 m
and over ................................................................................................................................ 22-28
E. Cargo Ships of 500 GT and over.......................................................................................... 22-29
F. Oil Tankers of 500 GT and over .......................................................................................... 22-37
G. Helicopter Decks .................................................................................................................. 22-39

Section 23 Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Cargo and Heavy
Cargo.............................................................................................................................23-1
A. Strengthenings for Bulk Cargo and Heavy Cargo................................................................... 23-1
B. Bulk Carriers .......................................................................................................................... 23-1
C. Ore Carriers ............................................................................................................................ 23-7
D. Allowable hold loading, considering flooding........................................................................ 23-8
E. Evaluation of Scantlings of Corrugated Transverse Watertight Bulkheads in Bulk Carriers
Considering Hold Flooding .................................................................................................. 23-11
F. Harmonised Notations and Corresponding Design Loading Conditions for Bulk Carriers .. 23-20
G. Fitting of a Forecastle for Bulk Carriers, Ore Carriers and Combination Carriers ............... 23-24
H. Transport of Steel Coils in Multi-Purpose Dry Cargo Ships ................................................ 23-24

Section 24 Oil Tankers ...................................................................................................................24-1

A. General ................................................................................................................................... 24-1
B. Strength of Girders and Transverses in the Cargo Tank Area .............................................. 24-12
C. Oiltight Longitudinal and Transverse Bulkheads ................................................................. 24-14
D. Wash Bulkheads ................................................................................................................... 24-15
E. Hatches ................................................................................................................................. 24-15
F. Structural Details at the Ship's End ...................................................................................... 24-16
G. Ships for the Carriage of Dry Cargo or Oil in Bulk.............................................................. 24-16
H. Product List 1 ....................................................................................................................... 24-18
J. Product List 2 ....................................................................................................................... 24-19
K. Additional Requirements for Tankers in Shuttle Service ..................................................... 24-21

Section 25 Tugs...............................................................................................................................25-1
A. General ................................................................................................................................... 25-1
B. Hull Structures........................................................................................................................ 25-1
C. Towing gear/Towing arrangement.......................................................................................... 25-3
D. Steering gear/Steering arrangement........................................................................................ 25-8
E. Anchoring/mooring equipment............................................................................................... 25-8
F. Weather tight integrity and stability ....................................................................................... 25-8
G. Escape routes and safety measures ......................................................................................... 25-9
H. Additional Requirements for Active Escort Tugs................................................................... 25-9
Section 26 Passenger Ships............................................................................................................ 26-1
A. General................................................................................................................................... 26-1
B. Documents for Approval........................................................................................................ 26-1
C. Watertight Subdivision........................................................................................................... 26-1
D. Double Bottom....................................................................................................................... 26-1
E. Superstructure ........................................................................................................................ 26-2
F. Openings in the Shell Plating ................................................................................................. 26-2
G. Materials for Closures of Openings........................................................................................ 26-2
H. Cross-Flooding Arrangements ............................................................................................... 26-2
I. Pipe Lines .............................................................................................................................. 26-2
J. Side Scuttles and Windows .................................................................................................... 26-3

Section 27 Special Purpose Ships.................................................................................................. 27-1

A. General................................................................................................................................... 27-1
B. Documents for Approval........................................................................................................ 27-1

Section 28 Subdivision and Stability of Cargo Ships and Passenger Ships............................... 28-1
A. General................................................................................................................................... 28-1
B. Onboard Stability Information ............................................................................................... 28-1
C. Double Bottom....................................................................................................................... 28-2
D. Watertight Bulkheads and Decks ........................................................................................... 28-2
E. External Openings.................................................................................................................. 28-3
F. Cross-Flooding Arrangements ............................................................................................... 28-3

Section 29 Work Ships................................................................................................................... 29-1

A. General................................................................................................................................... 29-1
B. Shell Plating, Frames ............................................................................................................. 29-1
C. Weather Deck......................................................................................................................... 29-1
D. Superstructures and Deckhouses ............................................................................................ 29-2
E. Access to Spaces .................................................................................................................... 29-2
F. Equipment .............................................................................................................................. 29-2

Section 30 Ships for Sheltered Water Service ............................................................................. 30-1

A. General................................................................................................................................... 30-1
B. Shell Plating ........................................................................................................................... 30-1
C. Watertight Bulkheads and Tank Bulkheads ........................................................................... 30-1
D. Deck Openings....................................................................................................................... 30-2
E. Equipment .............................................................................................................................. 30-2

Section 31 Barges and Pontoons ................................................................................................... 31-1

A. General................................................................................................................................... 31-1
B. Longitudinal Strength............................................................................................................. 31-1
C. Watertight Bulkheads and Tank Bulkheads ........................................................................... 31-2
D. Structural Details at the Ends ................................................................................................. 31-2
 E. Rudder .................................................................................................................................... 31-2
F. Pushing and Towing Devices, Connecting Elements.............................................................. 31-2
G. Equipment .............................................................................................................................. 31-3

Section 32 Dredgers........................................................................................................................32-1
A. General ................................................................................................................................... 32-1
B. Documents for Approval ........................................................................................................ 32-1
C. Principal Dimensions.............................................................................................................. 32-2
D. Longitudinal Strength ............................................................................................................. 32-2
E. Shell Plating ........................................................................................................................... 32-2
F. Deck ....................................................................................................................................... 32-2
G. Bottom Structure .................................................................................................................... 32-3
H. Hopper and Well Construction............................................................................................... 32-4
J. Box Keel................................................................................................................................. 32-5
K. Stern Frame and Rudder ......................................................................................................... 32-5
L. Bulwark, Overflow Arrangements.......................................................................................... 32-6
M. Self-Unloading Barges ........................................................................................................... 32-6
N. Equipment .............................................................................................................................. 32-7

Section 33 Strengthening against Collisions.................................................................................33-1

A. General ................................................................................................................................... 33-1
B. Calculation of the Deformation Energy.................................................................................. 33-1
C. Computation of the Critical Speed ......................................................................................... 33-3

Section 34 Special Requirements for In-Water Surveys .............................................................34-1

A. General ................................................................................................................................... 34-1
B. Special Arrangements for In-Water Surveys ......................................................................... 34-1
C. Documents and for Approval, Trials ...................................................................................... 34-1

Section 35 Corrosion Protection ...................................................................................................35-1

A. General Instructions................................................................................................................ 35-1
B. Shop Primers .......................................................................................................................... 35-1
C. Hollow Spaces........................................................................................................................ 35-1
D. Combination of Materials....................................................................................................... 35-2
E. Fitting-Out and Berthing Periods............................................................................................ 35-2
F. Corrosion Protection of Ballast Water Tanks......................................................................... 35-2
G. Corrosion Protection of Cargo Holds ..................................................................................... 35-2
H. Corrosion Protection of the Underwater Hull......................................................................... 35-2

Annex A Load Line Marks........................................................................................................... A-1

A. Load Line Marks of GL........................................................................................................... A-1

Annex B Ice Class Draught Marking.......................................................................................... B-1

A. Ice Class Draught Marking of GL ........................................................................................... B-1
I - Part 1 Section 1 A General, Definitions Chapter 1
GL 2012 Page 1–1

Section 1

General, Definitions

Note plementary Rules to both IACS Common Structural

Rules.
Passages printed in italics generally contain recom-
mendations and notes which are not part of the Clas-
new I-0, Section 2, Table 2.4 and Table 2.6
sification Rules. Requirements quoted in extracts of
For bulk carriers and oil tankers below each individual
statutory regulations, which are mandatory besides
length limit these GL Rules continue to apply under
Classification, may also be printed in italics.
particular consideration of Section 23 and Section 24.

new A.1.3
I-0, Section 2, Table 2.3 and 2.5

2. Ships deviating from the Construction Rules

A. Validity, Equivalence in their types, equipment or in some of their parts may
be classed, provided that their structures or equipment
is found to be equivalent to the Society's requirements
1. The Rules apply to seagoing steel ships
for the respective class.
classed 100A5 whose breadth to depth ratio is within
the range common for seagoing ships and the depth H
new A.1.2
of which is not less than:
– L/16 for unlimited range of service and 3. For Characters of Classification and Class
RSA (200) (Restricted Service Area) Notations see the GL Rules for Classification and
Surveys (I-0), Section 2.
– L/18 for RSA (50), RSA (20)

new A.2.1
– L/19 for RSA (SW)
Smaller depths may be accepted if proof is submitted 4. For ships suitable for in-water surveys which
of equal strength, rigidity and safety of the ship. will be assigned the Class Notation IW, the require-
ments of Section 34 are to be observed.

new A.1.1

I-0, Section 2, Table 2.11
Hull structural design of container ships with L ≥
150 m is to be carried out on the basis of the GL 5. Class Notations for ships subject to ex-
Structural Rules for Container Ships (I-1-5). tended strength analysis

new I-0, Section 2, Table 2.3 RSD Cargo hold analysis carried out by the
designer and examined by GL
Hull structural design of bulk carriers with L ≥ 90 m
contracted for construction on or after 1st April 2006, RSD (F25) Fatigue assessment based on 6,25 ⋅ 107
is to be carried out on the basis of the IACS Common load cycles of North Atlantic Spectrum
Structural Rules for Bulk Carriers. carried out by GL

I-0, Section 2, Table 2.4 RSD (F30) Fatigue assessment based on 7,5 ⋅ 107
load cycles of North Atlantic Spectrum
For bulk carriers not subject to the IACS Common carried out by GL
Structural Rules the requirements in Section 23 are
applicable. Fatigue assessment will be carried out for all hatch
opening corners on all deck levels, longitudinal frames

I-0, Section 2, Table 2.3 and butt welds of deck plating and side shell plating
Accordingly for double hull oil tankers with L ≥ 150 m (where applicable).
the IACS Common Structural Rules for Double Hull RSD (ACM) Additional corrosion margin according
Oil Tankers are applicable from this date on. For these to detailed listings in the technical file.
ships Section 24, A. is to be observed in addition. Analysis carried out by GL.

I-0, Section 2, Table 2.5 and 2.6 RSD (gFE) Global finite element analysis carried out
in accordance with the GL Guidelines for
Further rules relevant for hull structural design not co- Global Strength Analysis of Container
vered by the IACS Common Structural Rules are Ships (V-1-1)
issued by GL in special companion volumes as com-
Chapter 1 Section 1 E General, Definitions I - Part 1
Page 1–2 GL 2012

I-0, Section 2, Table 2.10 Chapter B.2.3 of the above Code has only to be taken
into account on special advice of the competent Ad-
ministration.
Special attention is to be paid to the effect of free
B. Restricted Service Areas surfaces of liquids in partly filled tanks. Special pre-
cautions shall be taken for tanks which, due to the
1. For determining the scantlings of the longitu- geometry, may have excessive free surface moments,
dinal and transverse structures of ships intended to thus jeopardizing the initial stability of the vessel, e.g.
operate within one of the restricted service areas RSA tanks in the double bottom reaching from side to side.
(200), RSA (50), RSA (20) and RSA (SW), the dynamic In general such tanks shall be avoided.
loads may be reduced as specified in Section 4 and 5.
Evidence of approval by the competent Administra-
tion concerned may be accepted for the purpose of
2. For the definition of the restricted service classification.
areas RSA (200), RSA (50), RSA (20) and RSA (SW)
see the GL Rules for Classification and Surveys (I-0), The above provisions do not affect any intact stability
Section, 2, C.3.1.1. requirements resulting from damage stability calcula-
tions, e.g. for ships to which the symbol  is assigned.

I-0, Section 2, C.3.1

2. Ships with proven damage stability

Ships with proven damage stability will be assigned
C. Ships for Special Services the symbol . In the Register Book and in an appen-
When a ship is intended to carry special cargoes (e.g. dix to the Certificate the proof of damage stability will
logs) the loading, stowage and discharging of which be specified by a code as detailed in the GL Rules for
may cause considerable stressing of structures in way Classification and Surveys (I-0), Section 2, C.2.4.2.
of the cargo holds, such structures are to be investi-
gated for their ability to withstand these loads. 2.1 Damage stability requirements applicable
to bulk carriers

new Section 5, B.3.2
2.1.1 Bulk carriers of 150 m in length and upwards
of single side skin construction, designed to carry solid
bulk cargoes having a density of 1 000 kg/m3 and above
D. Accessibility shall, when loaded to the summer load line, be able to
withstand flooding of any one cargo hold in all loading
1. All parts of the hull are to be accessible for conditions and remain afloat in a satisfactory condition
survey and maintenance. of equilibrium, as specified in the next 2.1.2 paragraph.

new Section 27, D.1.1 Subject to the provisions of that paragraph, the condi-
tion of equilibrium after flooding shall satisfy the
2. For safe access to the cargo area of oil tank- condition of equilibrium laid down in the annex to
ers and bulk carriers see Section 21, N. resolution A.320(IX), Regulation equivalent to regula-
tion 27 of the International Convention on Load Lines,
1966, as amended by resolution A.514(13). The as-
sumed flooding need only take into account flooding
of the cargo hold space. The permeability of a loaded
E. Stability
hold shall be assumed as 0,9 and the permeability of
an empty hold shall be assumed as 0,95, unless a per-
1. General meability relevant to a particular cargo is assumed for
Ships with a length of 24 m and above will be assigned the volume of a flooded hold occupied by cargo and a
Class only after it has been demonstrated that their permeability of 0,95 is assumed for the remaining
intact stability is adequate for the service intended. empty volume of the hold.

Adequate intact stability means compliance with stan- Bulk carriers which have been assigned a reduced
dards laid down by the relevant Administration. GL freeboard in compliance with the provisions of para-
reserve the right to deviate there from, if required for graph (8) of the regulation equivalent to regulation 27
special reasons, taking into account the ships' size and of the International Convention on Load Lines, 1966,
type. The level of intact stability for ships of all sizes adopted by resolution A.320(IC), as amended by reso-
in any case should not be less than that provided by lution A.514(13), may be considered as complying
the International Code on Intact Stability (2008 IS with paragraph 2.1.1.
Code), unless special operational restrictions reflected
2.1.2 On bulk carriers which have been assigned
in the class notation render this possible.
reduced freeboard in compliance with the provisions of
regulation 27(8) set out in Annex B of the Protocol of
I - Part 1 Section 1 G General, Definitions Chapter 1
GL 2012 Page 1–3

1988 relating to the International Convention on Load not mandatory, the following guidelines and regula-
Lines, 1966, the condition of equilibrium after flooding tions are recommended:
shall satisfy the relevant provisions of that Protocol.
vibration load to the crew:
2.1.3 Ships with assigned reduced freeboards in-
tended to carry deck cargo shall be provided with a – measurement and analysis techniques:
limiting GM or KG curve required by SOLAS Chap- according to ISO 6954, ed. 2000
ter II-1, Regulation 25-8, based on compliance with
the probabilistic damage stability analysis of Part B-1 – limit values:
(see IACS Unified Interpretation LL 65).
according to ISO 6954, depending on ship type
and location within the ship 1
3. Anti-heeling devices
– ships flying the German Flag:
3.1 If tanks are used as anti-heeling devices,
effects of maximum possible tank moments on intact Guidelines of the Accident Prevention Regula-
stability are to be checked. A respective proof has to tions of See-Berufsgenossenschaft
be carried out for several draughts and taking maxi-
mum allowable centres of gravity resulting from the – inconvenience to passengers due to ship vibra-
stability limit curve as a basis. In general the heeling tions:
angle shall not be more than 10°. GL Class Notation Harmony Class according to
the GL Rules on Rating Noise and Vibrations for
3.2 If the ship heels more than 10°, the GL Rules Comfort, Cruise Ships (I-1-16)
for Machinery Installations (I-1-2), Section 11, P.1.4
have to be observed. – vibrations of machinery, installations and other
equipment:
3.3 All devices have to comply with the GL
Rules for Electrical Installations (I-1-3), Section 7, G. GL Rules for Machinery Installations (I-1-2),
Section 1

new Section 28

new B.1

2. Noise
F. Vibrations and Noise Suitable precautions are to be taken to keep noises as
low as possible particularly in the crew's quarters,
Note working spaces, passengers' accommodation, etc.
Attention is drawn to regulations concerning noise
1. Mechanical vibrations level limitations, if any, of the flag administration.
Operating conditions which are encountered most fre-
new B.2
quently should be kept free as far as possible from re-
sonance vibrations of the ship hull and individual struc-
tural components. Therefore, the exciting forces coming
from the propulsion plant and pressure fluctuations G. Documents for Approval
should be limited as far as possible. Beside the selec-
tion of the propulsion units particular attention is to 1. The following documents are to be submitted
be given to the ship's lines including the stern post, as
to GL. To facilitate a smooth and efficient approval
well as to the minimisation of possible cavitation. In
the shaping of the bow it should be kept in mind that a process they shall be submitted electronically via
large flare above the waterline will not only cause GLOBE 2. In specific cases and following prior agree-
very high local slamming pressures, but will also ment with GL they can also be submitted in paper form
excite increasingly whipping vibrations of the ship's in triplicate.
hull. If critical excitation loads cannot be eliminated,
I-0, Section 2, D.2
appropriate measures are to be taken on the basis of
theoretical investigations at an early design stage.
For example, the risk of large global and local struc-
tural vibrations can be minimized by a global or local
vibration analysis, respectively, to be conducted dur-
ing the steel structures design phase.
1 The GL Service Group Vibration is ready to provide support to
Limit values for vibrations aboard ships may be as- this activity.
sessed under several aspects. If the application of 2 Detailed information about the secured GL system GLOBE
other national or international rules or standards is can be found on GL's website www.gl-group.com/globe.
Chapter 1 Section 1 G General, Definitions I - Part 1
Page 1–4 GL 2012

1.1 Midship section
I-0, Section 2, D.2

The cross sectional plans (midship section, other typi- 1.7.2 Docking plan and docking calculation ac-
cal sections) shall contain all necessary data on the cording to Section 8, D. are to be submitted.
scantlings of the longitudinal and transverse hull struc-
ture as well as details of anchor and mooring equip-
I-0, Section 2, D.2
ment.

I-0, Section 2, D.2 1.8 Engine and boiler seatings
Drawings of the engine and boiler seatings, the bottom
1.2 Longitudinal section structure under the seatings and of the transverse
structures in the engine room, with details on fastening
The plan of longitudinal sections shall contain all
of the engine foundation plate to the seating, as well as
necessary details on the scantlings of the longitudinal
type and output of engine.
and transverse hull structure and on the location of the
watertight bulkheads and the deck supporting struc-
I-0, Section 2, D.2
tures, the arrangement of superstructures and deck
houses, as well as supporting structures of cargo 1.9 Stem and stern post, and rudder
masts, cranes, etc.
Drawings of stem and stern post, of rudder, including

I-0, Section 2, D.2
rudder support. The rudder drawings shall contain
details on the ship's speed, the bearing materials to be
1.3 Decks employed, and the ice strengthening.
Plans of the decks showing the scantlings of the deck Drawings of propeller brackets and shaft exits.
structures, length and breadth of cargo hatches, open-
ings above the engine and boiler room, and other deck
I-0, Section 2, D.2
openings. On each deck, it has to be stated which deck
load caused by cargo is to be assumed in determining 1.10 Hatchways
the scantlings of the decks and their supports. Fur-
thermore, details on possible loads caused by fork lift Drawings of hatchway construction and hatch covers.
trucks and containers are to be stated.
The drawings of the hatch coamings shall contain all

I-0, Section 2, D.2 details, e. g., bearing pads with all relevant details
regarding loads and substructures, including cut-outs
1.4 Shell for the fitting of equipment such as stoppers, securing
devices, etc. necessary for the operation of hatches.
Drawings of shell expansion, containing full details on
the location and size of the openings and drawings of The structural arrangement of stays and stiffeners and
the sea chests. of their substructures is to be shown.

I-0, Section 2, D.2
I-0, Section 2, D.2

1.5 Ice strengthening 1.11 Longitudinal strength

The drawings listed in 1.1 – 1.4, 1.6, 1.7 and 1.9 shall All necessary documents for the calculation of bend-
contain all necessary details on ice strengthening. ing moments, shear forces and, if necessary, torsional

I-0, Section 2, D.2 moments. This includes the mass distribution for the
envisaged loading conditions and the distribution of
section moduli and moduli of inertia over the ship's
1.6 Bulkheads length.
Drawings of the transverse, longitudinal and wash bulk-
Loading Guidance Information according to Section 5,
heads and of all tank boundaries, with details on densi-
A.4.
ties of liquids, heights of overflow pipes and set pres-
sures of the pressure or vacuum relief valves (if any).
I-0, Section 2, D.2

I-0, Section 2, D.2
1.12 Materials
1.7 Bottom structure
The drawings mentioned in 1.1 – 1.10 and 1.15 shall
1.7.1 Drawings of single and double bottom show- contain details on the hull materials (e.g. hull struc-
ing the arrangement of the transverse and longitudinal tural steel grades, standards, material numbers).
girders as well as the water and oiltight subdivision of Where higher tensile steels or materials other than
the double bottom. For bulk and ore carriers, data are ordinary hull structural steels are used, drawings for
to be stated on the maximum load on the inner bottom. possible repairs have to be placed on board.

I-0, Section 2, D.2
I - Part 1 Section 1 H General, Definitions Chapter 1
GL 2012 Page 1–5

1.13 Weld joints bulkheads as well as cross flooding arrangements and

discharge openings.
The drawings listed in 1.1 – 1.10 and 1.15 shall con-
tain details on the welded joints e.g. weld shapes and
I-0, Section 2, D.2
dimensions and weld quality. For the relevant data for
manufacturing and testing of welded joints see Rules 1.20 Structural fire protection
for Welding.
In addition to the fire control and safety plan also

I-0, Section 2, D.2 drawings of the arrangement of divisions (insulation,
A-, B- and C-divisions) including information regard-
1.14 Lashing and stowage devices ing GL-approval number.
Drawings containing details on stowage and lashing of Drawings of air conditioning and ventilation plants.
cargo (e.g. containers, car decks).

I-0, Section 2, D.2
In the drawings the location of the connections and the
appropriate substructures at the ship shall be shown in 1.21 Special particulars for examination
detail.
1.21.1 For ships constructed for special purposes,

I-0, Section 2, D.2 drawings and particulars of those parts, examination
of which is necessary for judging the vessel's strength
1.15 Substructures
and safety.
Drawings of substructures below steering gears, wind-

I-0, Section 2, D.2
lasses and chain stoppers as well as masts and boat
davits together with details on loads to be transmitted 1.21.2 Additional documents and drawings may be
into structural elements. required, if deemed necessary.

I-0, Section 2, D.2
I-0, Section 2, D.2
1.16 Closing condition 1.21.3 Any deviations from approved drawings are
For assessing the closing condition, details on closing subject to approval before work is commenced.
appliances of all openings on the open deck in position
I-0, Section 2, D.2
1 and 2 according to ICLL and in the shell, i.e.
hatchways, cargo ports, doors, windows and side scut-
tles, ventilators, erection openings, manholes, sanitary
discharges and scuppers. H. Definitions

I-0, Section 2, D.2
1. General
1.17 Watertight Integrity Unless otherwise mentioned, the dimensions accord-
Drawings containing the main- and local internal ing to 2. and 3. are to be inserted [m] into the formulae
subdivision of the hull. Information about arrange- stated in the following Sections.
ments of watertight longitudinal- and transverse bulk-
units included in each definition
heads, cargo hold entrances, air ventilation ducts,
down- and crossflooding arrangements.
2. Principal dimensions

I-0, Section 2, D.2
2.1 Length L
1.18 Intact stability
The length L is the distance in metres on the summer
Analysis of an inclining experiment to be performed load waterline from the fore side of the stem to the
upon completion of newbuildings and/or conversions, centre of the rudder stock. L is not to be less than
for determining the light ship data. 96 % and need not be greater than 97 % of the ex-
treme length of the summer load waterline. In ships
Intact stability particulars containing all information
with unusual stern and bow arrangement, the length L
required for calculation of stability in different loading
will be specially considered.
conditions. For initial assignment of class to new-
buildings preliminary particulars will be acceptable.
new A.3.1.1

I-0, Section 2, D.2
2.2 Length Lc (according to ICLL, MARPOL
1.19 Damage stability 73/78, IBC-Code and IGC-Code)

Damage stability particulars containing all information The length Lc is to be taken as 96 % of the total length
required for establishing unequivocal condition for on a waterline at 85 % of the least moulded depth Hc
intact stability. A damage control plan with details on measured from the top of the keel, or as the length
watertight subdivision, closable openings in watertight from the fore side of the stem to the axis of the rudder
Chapter 1 Section 1 H General, Definitions I - Part 1
Page 1–6 GL 2012

stock on that waterline, if that be greater. In ships 5. Ship's speed v0

designed with a rake of keel the waterline on which
Maximum service speed [kn], which the ship is de-
this length is measured shall be parallel to the de-
signed to maintain at the summer load line draught
signed waterline. and at the propeller RPM corresponding to MCR

new A.3.1.1 (maximum continuous rating).

For the definition of the least moulded depth Hc see In case of controllable pitch propellers the speed v0 is
to be determined on the basis of maximum pitch.
ICLL, Annex I, Chapter I, Regulation 3 (5).

new A.3.1.1
(direct definition of Hc included in new A.3.1.1)
6. Definition of decks
2.3 Forward perpendicular F.P.
The forward perpendicular coincides with the foreside 6.1 Bulkhead deck
of the stem on the waterline on which the respective Bulkhead deck is the deck up to which the watertight
length L or Lc is measured. bulkheads are carried.

new A.3.1.1
new A.3.2

2.4 Breadth B 6.2 Freeboard deck

The breadth B is the greatest moulded breadth of the Freeboard deck is the deck upon which the freeboard
ship. calculation is based.

new A.3.1.1
new A.3.2

2.5 Depth H 6.3 Strength deck

The depth H is the vertical distance, at the middle of Strength deck is the deck or the parts of a deck which
the length L, from the base line to top of the deck form the upper flange of the effective longitudinal
beam at side on the uppermost continuous deck. structure.

In way of effective superstructures the depth is to be
new A.3.2

measured up to the superstructure deck for determin-
ing the ship's scantlings. 6.4 Weather deck

new A.3.1.1 All free decks and parts of decks exposed to the sea
are defined as weather deck.
2.6 Draught T
new A.3.2
The draught T is the vertical distance at the middle of
6.5 Lower decks
the length L from base line to freeboard marking for
summer load waterline. For ships with timber load line Starting from the first deck below the uppermost con-
the draught T is to be measured up to the freeboard tinuous deck, the decks are defined as 2nd, 3rd deck, etc.
mark for timber load waterline.

new A.3.2

new A.3.1.1
6.6 Superstructure decks
3. Frame spacing a The superstructure decks situated immediately above
the uppermost continuous deck are termed forecastle
The frame spacing a will be measured from moulding
edge to moulding edge of frame. deck, bridge deck and poop deck. Superstructure
decks above the bridge deck are termed 2nd, 3rd su-

new A.3.1.1 perstructure deck, etc.

new A.3.2
4. Block coefficient CB
6.7 Position of hatchways, doorways and ven-
Moulded block coefficient at load draught T, based on tilators
length L.
For the arrangement of hatches, doors and ventilators
moulded volume of displacement [m3 ] at T the following areas are defined:
CB =
L⋅B⋅T Pos. 1 – on exposed freeboard decks

new A.3.1.1 – on raised quarter decks
I - Part 1 Section 1 K General, Definitions Chapter 1
GL 2012 Page 1–7

– on the first exposed superstructure deck J. International Conventions and Codes

above the freeboard deck within the for-
Where reference is made of international Conventions
ward quarter of Lc
and Codes these are defined as follows:
Pos. 2 – on exposed superstructure decks aft of the
new A.2.2.2
forward quarter of Lc located at least one
standard height of superstructure above
1. ICLL
the freeboard deck
International Convention on Load Lines, 1966, as
– on exposed superstructure decks within amended.
the forward quarter of Lc located at least
two standard heights of superstructure
new A.2.2.2
above the freeboard deck
2. MARPOL

new A.3.3
International Convention for the Prevention of Pollu-
tion from Ships, 1973 including the 1978 Protocol as
7. Material properties amended.

new A.2.2.2
7.1 Yield strength ReH

The yield strength ReH [N/mm2] of the material is 3. SOLAS

defined as the nominal upper yield point. In case of International Convention for the Safety of Life at Sea,
materials without a marked yield point, the proof 1974, as amended.
stress Rp is to be used instead. See also Section 2, D.
and E. and GL Rules Principles and Test Procedures
new A.2.2.2
(II-1-1), Section 2, D.
4. IBC Code

new A.3.1.2
International Code for the Construction and Equip-
ment of Ships Carrying Dangerous Chemicals in Bulk
7.2 Tensile strength Rm as amended.
Rm [N/mm2] is the minimum tensile strength of the
new A.2.2.2
material. See also GL Rules Principles and Test Pro-
cedures (II-1-1), Section 2, D. 5. IGC Code

new A.3.1.2 International Code for the Construction and Equipment
of Ships Carrying Liquefied Gases in Bulk as amended.
7.3 Proof stress Rp
new A.2.2.2
The proof stress Rp [N/mm2] is the stress that will
6. IMSBC Code
cause a specified permanent extension of a specimen
of a tensile test. The specified permanent extension is International Maritime Solid Bulk Cargoes Code.
denoted in the index.

new A.2.2.2
Rp0,2 = 0,2 % proof stress

Rp1,0 = 1,0 % proof stress

K. Rounding-Off Tolerances
See also GL Rules Principles and Test Procedures (II-
1-1), Section 2, D. Where in determining plate thicknesses in accordance
with the provisions of the following Sections the fig-

new A.3.1.2 ures differ from full or half mm, they may be rounded
off to full or half millimetres up to 0,2 or 0,7; above
7.4 Young's modulus E 0,2 or 0,7 mm they are to be rounded up.
If plate thicknesses are not rounded the calculated
The Young's modulus E [N/mm2] is to be set to: required thicknesses shall be shown in the drawings.
E = 2,06 ⋅ 105 N/mm2 for mild and higher strength The section moduli of profiles usual in the trade and
structural steels including the effective width according to Section 3,
E. and F. may be 3 % less than the required values
= 0,69 ⋅ 105 N/mm2 for aluminium alloys according to the following rules for dimensioning.

new A.3.1.2
new C
Chapter 1 Section 1 M General, Definitions I - Part 1
Page 1–8 GL 2012

L. Regulations of National Administrations
new E.4

For the convenience of the user of these Rules several 2.4.1 Strength
Sections contain for guidance references to such regu-
lations of national administrations, which deviate from Linear and/or non-linear strength calculations with the
the respective rule requirements of this Society but FE-method:
which may have effect on scantlings and construction.
These references have been specially marked. For an automated performance of these calculations, a
number of effective pre- and post processing pro-
Compliance with these regulations of national admini- grammes is at disposal:
strations is not conditional for class assignment.
– calculation of seaway loads as per modified strip

new D method or by 3 D-panel method
– calculation of resultant accelerations to ensure
quasi-static equilibrium
M. Computer Programs
– calculation of composite structures

1. General – evaluation of deformations, stresses, buckling

behaviour, ultimate strength and local stresses,
1.1 In order to increase the flexibility in the assessment of fatigue strength
structural design of ships GL also accepts direct calcu-

new E.4.1
lations with computer programs. The aim of such
analyses should be the proof of equivalence of a de-
sign with the rule requirements. 2.4.2 Vibrations

new E.1 Calculation of free vibrations with the FE-method as

well as forced vibrations due to harmonic or shock
1.2 Direct calculations may also be used in order excitation:
to optimise a design; in this case only the final results – global vibrations of hull, aft ship, deckhouse, etc.
are to be submitted for examination.
– vibrations of major local components, such as
2. General programs rudders, radar masts, etc.
– local vibrations of plate fields, stiffeners and
2.1 The choice of computer programs according panels
to "State of the Art" is free. The programs may be
checked by GL through comparative calculations with – vibrations of simply or double-elastically
predefined test examples. A generally valid approval mounted aggregates
for a computer program is, however, not given by GL.
A number of pre- and post processing programs

new E.3 is available here as well for effective analyses:

2.2 Direct calculations may be used in the fol- – calculation of engine excitation forces/mo-
lowing fields ments
– global strength – calculation of propeller excitation forces
(pressure fluctuations and shaft bearing reac-
– longitudinal strength
tions)
– beams and grillages
– calculation of hydrodynamic masses
– detailed strength
– graphic evaluation of amplitude level as per
2.3 For such calculation the computer model, the ISO 6954 recommendations or as per any
boundary condition and load cases are to be agreed other standard
upon with GL. The calculation documents are to be – noise predictions
submitted including input and output. During the ex-
amination it may prove necessary that GL perform
new E.4.2
independent comparative calculations.

new E.2 2.4.3 Collision resistance
Calculation of the structure's resistance against colli-
2.4 GL is prepared to carry out the following sion for granting the additional class notation COLL
calculations of this kind within the marine advisory according to Section 33.
services:

new E.4.3
I - Part 1 Section 1 N General, Definitions Chapter 1
GL 2012 Page 1–9

3. Specific programs related to Rules
new I-0, Section 2, D.5.1.2.1

3.1 General 1.2.2 Upon inspection and corrections by the

GL has developed the computer program "POSEI- manufacturing plant, the structural components are to
DON" as an aid to fast and reliable dimensioning a be shown to the GL Surveyor for inspection, in suit-
hull's structural members according to GL Rules, and able sections, normally in unpainted condition and
for direct strength calculations. enabling proper access for inspection.

new F.1
new I-0, Section 2, D.5.1.2.2

3.2 POSEIDON
1.2.3 The Surveyor may reject components that
POSEIDON includes both the traditional dimension- have not been adequately checked by the plant and may
ing as well as the automatic optimisation of scantlings demand their re-submission upon successful comple-
by means of direct calculations according to the FE- tion of such checks and corrections by the plant.
method.

new I-0, Section 2, D.5.1.2.3
POSEIDON is supported on PCs by Microsoft Win-
dows , and a hotline has been set up to assist users.
Further information is available via the GL-homepage, 2. Structural details
at inspection offices world-wide and at GL Head Of-
fice.
2.1 Details in manufacturing documents

new F.2
2.1.1 All significant details concerning quality and
3.3 GL RULES and Programs
functional ability of the component concerned shall be
GLRP is available on CD-ROM. It includes the word- entered in the manufacturing documents (workshop
ing of GL-Rules and an elementary program for di- drawings, etc.). This includes not only scantlings but
mensioning the structural members of the hull. - where relevant - such items as surface conditions
(e.g. finishing of flame cut edges and weld seams),
GLRP can be used together with POSEIDON.
and special methods of manufacture involved as well

new F.3 as inspection and acceptance requirements and where
N. Workmanship relevant permissible tolerances. So far as for this aim a
standard shall be used (works or national standard
etc.) it shall be harmonized with GL. This standard
1. General
shall be based on the IACS Recommendation 47 Ship-
building and Repair Quality Standard for New Con-
1.1 Requirements to be complied with by the
struction. For weld joint details, see Section 19, A.1.
manufacturer

1.1.1 The manufacturing plant shall be provided
new I-0, Section 2, D.5.2.1.1
with suitable equipment and facilities to enable proper
handling of the materials, manufacturing processes, 2.1.2 If, due to missing or insufficient details in the
structural components, etc. GL reserve the right to manufacturing documents, the quality or functional abil-
inspect the plant accordingly or to restrict the scope of ity of the component cannot be guaranteed or is doubtful,
manufacture to the potential available at the plant. GL may require appropriate improvements. This includes
the provision of supplementary or additional parts (for

new I-0, Section 2, D.5.1.1.1
example reinforcements) even if these were not required
1.1.2 The manufacturing plant shall have at its at the time of plan approval or if - as a result of insuffi-
disposal sufficiently qualified personnel. GL is to be cient detailing - such requirement was not obvious.
advised of the names and areas of responsibility of all
supervisory and control personnel. GL reserve the
new I-0, Section 2, D.5.2.1.2
right to require proof of qualification.

new I-0, Section 2, D.5.1.1.2 2.2 Cut-outs, plate edges

1.2 Quality control 2.2.1 The free edges (cut surfaces) of cut-outs,
hatch corners, etc. are to be properly prepared and are
1.2.1 As far as required and expedient, the manu- to be free from notches. As a general rule, cutting drag
facturer's personnel has to examine all structural com- lines, etc. shall not be welded out, but are to be
ponents both during manufacture and on completion, smoothly ground. All edges should be broken or in
to ensure that they are complete, that the dimensions cases of highly stressed parts, should be rounded off.
are correct and that workmanship is satisfactory and
meets the standard of good shipbuilding practice.
new I-0, Section 2, D.5.2.2.1
Chapter 1 Section 1 N General, Definitions I - Part 1
Page 1–10 GL 2012

2.4 Assembly, alignment

2.2.2 Free edges on flame or machine cut plates or
flanges are not to be sharp cornered and are to be 2.4.1 The use of excessive force is to be avoided
finished off as laid down in 2.2.1 This also applies to during the assembly of individual structural compo-
cutting drag lines, etc., in particular to the upper edge nents or during the erection of sections. As far as
of sheer strake and analogously to weld joints, possible major distortions of individual structural
changes in sectional areas or similar discontinuities. components should be corrected before further assem-
bly.

new I-0, Section 2, D.5.2.2.2

new I-0, Section 2, D.5.2.4.1

2.3 Cold forming 2.4.2 Girders, beams, stiffeners, frames, etc. that
are interrupted by bulkheads, decks, etc. shall be accu-
2.3.1 For cold forming (bending, flanging, bead- rately aligned. In the case of critical components,
ing) of plates the minimum average bending radius control drillings are to be made where necessary,
shall not fall short of 3 t (t = plate thickness) and shall which are then to be welded up again on completion.
be at least 2 t. Regarding the welding of cold formed
new I-0, Section 2, D.5.2.4.2
areas, see Section 19, B.2.6.
2.4.3 After completion of welding, straightening

new I-0, Section 2, D.5.2.3.1 and aligning shall be carried out in such a manner that
the material properties will not be influenced signifi-
2.3.2 In order to prevent cracking, flame cutting cantly. In case of doubt, GL may require a procedure
flash or sheering burrs shall be removed before cold test or a working test to be carried out.
forming. After cold forming all structural components
new I-0, Section 2, D.5.2.4.3
and, in particular, the ends of bends (plate edges) are
to be examined for cracks. Except in cases where edge
cracks are negligible, all cracked components are to be 3. Corrosion protection
rejected. Repair welding is not permissible. Section 35 is to be noticed.

new I-0, Section 2, D.5.2.3.2
I - Part 1 Section 2 B Materials Chapter 1
GL 2012 Page 2–1

Section 2

Materials

A. General fixed at 315, 355 and 390 N/mm2 respectively. Where

higher strength hull structural steel is used, for scant-
1. All materials to be used for the structural ling purposes the values in Table 2.1 are to be used for
members indicated in the Construction Rules are to be the material factor k mentioned in the various Sec-
in accordance with the GL Rules for Metallic Materi- tions:
als (II-1). Materials the properties of which deviate Table 2.1 Material factor k
from these Rule requirements may only be used upon
special approval.
ReH [N/mm2] k

new B.1.1
315 0,78
355 0,72
B. Hull Structural Steel for Plates and Sec- 390 0,66
tions
For higher strength hull structural steel with other
1. Normal strength hull structural steel yield strengths up to 390 N/mm2, the material factor k
may be determined by the following formula:
1.1 Normal strength hull structural steel is a hull
structural steel with a yield strength ReH of 235 N/mm2 295
and a tensile strength Rm of 400 – 520 N/mm2. k =
R eH + 60

new A.2
Note
1.2 The material factor k in the formulae of the
following Sections is to be taken 1,0 for normal Especially when higher strength hull structural steels
strength hull structural steel. are used, limitation of permissible stresses due to
buckling and fatigue strength criteria may be re-

new A.2 quired.

1.3 Normal strength hull structural steel is
new A.2

grouped into the grades GL–A, GL–B, GL–D, GL–E,
which differ from each other in their toughness prop- 2.2 Higher strength hull structural steel is
erties. For the application of the individual grades for grouped into the following grades, which differ from
the hull structural members, see 3. each other in their toughness properties:

new A.2 GL–A 32/36/40
GL–D 32/36/40
1.4 If for special structures the use of steels with
yield properties less than 235 N/mm2 has been ac- GL–E 32/36/40
cepted, the material factor k is to be determined by:
GL–F 32/36/40
235
k = In Table 2.7 the grades of the higher strength hull
R eH structural steels are marked by the letter "H".

new A.2
2. Higher strength hull structural steels
2.3 Where structural members are completely or
2.1 Higher strength hull structural steel is a hull partly made from higher strength hull structural steel,
structural steel, the yield and tensile properties of a suitable Notation will be entered into the ship's cer-
which exceed those of normal strength hull structural tificate.
steel. According to the GL Rules for Metallic Materi-
new B.1.3
als (II-1), for three groups of higher strength hull
structural steels the yield strength ReH has been
Chapter 1 Section 2 B Materials I - Part 1
Page 2–2 GL 2012

3.2 Material selection for longitudinal struc-

2.4 In the drawings submitted for approval it is to tural members
be shown which structural members are made of
Materials in the various strength members are not to
higher strength hull structural steel. These drawings
be of lower grade than those corresponding to the mate-
are to be placed on board in case any repairs are to be
rial classes and grades specified in Table 2.2 to Table
carried out.
2.8. General requirements are given in Table 2.2,

new B.1.4 while additional minimum requirements for ships with
length exceeding 150 m and 250 m, bulk carriers sub-
2.5 Regarding welding of higher strength hull ject to the requirements of SOLAS regulation XII/
structural steel, see GL Rules for Welding (II-3). 6.5.3, and ships with ice strengthening are given in
Table 2.3 to Table 2.6. The material grade require-

already implemented in Section 19 ments for hull members of each class depending on
3. Material selection for the hull the thickness are defined in Table 2.8.

3.1 Material classes
new B.2.2

For the material selection for hull structural members For structural members not specifically mentioned in
material classes as given in Table 2.2 are defined. Table 2.2, grade A/AH material may generally be used.

new B.2.1
new B.2.1

I - Part 1 Section 2 B Materials Chapter 1
GL 2012 Page 2–3

Table 2.2 Material classes and grades for ships in general

Structural member category Material class / grade

Secondary:
A1. Longitudinal bulkhead strakes, other than that be- – Class I within 0,4 L amidships
longing to the Primary category – Grade A/AH outside 0,4 L amidships
A2. Deck plating exposed to weather, other than that
belonging to the Primary or Special category
A3. Side plating
Primary:
B1. Bottom plating, including keel plate – Class II within 0,4 L amidships
B2. Strength deck plating, excluding that belonging to – Grade A/AH outside 0,4 L amidships
the Special category
B3. Continuous longitudinal members above strength
deck, excluding hatch coamings
B4. Uppermost strake in longitudinal bulkhead
B5. Vertical strake (hatch side girder) and uppermost
sloped strake in top wing tank
Special:
C1. Sheer strake at strength deck 1 – Class III within 0,4 L amidships
C2. Stringer plate in strength deck 1 – Class II outside 0,4 L amidships
C3. Deck strake at longitudinal bulkhead, excluding deck – Class I outside 0,6 L amidships
plating in way of inner-skin bulkhead of double-hull
ships 1
C4. Strength deck plating at outboard corners of cargo – Class III within 0,4 L amidships
hatch openings in container carriers and other ships – Class II outside 0,4 L amidships
with similar hatch opening configurations – Class I outside 0,6 L amidships
– Min. Class III within cargo region
C5. Strength deck plating at corners of cargo hatch open- – Class III within 0,6 L amidships
ings in bulk carriers, ore carriers, combination carriers – Class II within rest of cargo region
and other ships with similar hatch opening configura-
tions
C6. Bilge strake in ships with double bottom over the – Class II within 0,6 L amidships
full breadth and length less than 150 m 1 – Class I outside 0,6 L amidships
C7. Bilge strake in other ships 1 – Class III within 0,4 L amidships
– Class II outside 0,4 L amidships
– Class I outside 0,6 L amidships
C8. Longitudinal hatch coamings of length greater than – Class III within 0,4 L amidships
0,15 L – Class II outside 0,4 L amidships
C9. End brackets and deck house transition of longitudi- – Class I outside 0,6 L amidships
nal cargo hatch coamings – Not to be less than grade D/DH
1 Single strakes required to be of Class III within 0,4 L amidships are to have breadths not less than 800 + 5 L [mm] need not be greater
than 1800 mm, unless limited by the geometry of the ship's design.
Chapter 1 Section 2 B Materials I - Part 1
Page 2–4 GL 2012

Table 2.3 Minimum material grades for ships with length exceeding 150 m and single strength deck

Structural member category Material grade

Longitudinal strength members of strength deck plating Grade B/AH within 0,4 L amidships

Continuous longitudinal strength members above strength

Grade B/AH within 0,4 L amidships
deck
Single side strakes for ships without inner continuous
longitudinal bulkhead(s) between bottom and the strength Grade B/AH within cargo region
deck

Table 2.4 Minimum material grades for ships with length exceeding 250 m

Structural member category Material grade

Shear strake at strength deck 1 Grade E/EH within 0,4 L amidships
Stringer plate in strength deck 1 Grade E/EH within 0,4 L amidships
Bilge strake 1 Grade D/DH within 0,4 L amidships
1 Single strakes required to be of Grade E/EH and within 0,4 L amidships are to have breadths not less than 800 + 5 L [mm], need not be
greater than 1800 mm, unless limited by the geometry of the ship's design.

Table 2.5 Minimum material grades for single-side skin bulk carriers subjected to SOLAS regulation
XII/6.5.3

Structural member category Material grade

Lower bracket of ordinary side frame 1, 2 Grade D/DH
Side shell strakes included totally or partially between the
two points located to 0,125 ℓ above and below the intersec-
Grade D/DH
tion of side shell and bilge hopper sloping plate or inner
bottom plate 2
1 The term "lower bracket" means webs of lower brackets and webs of the lower part of side frames up to the point of 0,125 ℓ above the
intersection of side shell and bilge hopper sloping plate or inner bottom plate.
2 The span of the side frame ℓ is defined as the distance between the supporting structures.

Table 2.6 Minimum material grades for ships with ice strengthening

Structural member category Material grade

Shell strakes in way of ice strengthening area for plates Grade B/AH

Table 2.7 Minimum material grades in the area of crane columns and foundations

> 12,5 > 25 > 70

Thickness t [mm]
≤ 12,5 ≤ 25 ≤ 70

Minimum material grade A/AH B/AH D/DH E/EH

The requirements for material grades are valid for design temperatures up to 0 °C. For lower design temperatures the requirements for
material grades defined in GL Rules for Loading Gear on Seagoing Ships and Offshore Installations (VI-2-2) are to be considered.
I - Part 1 Section 2 B Materials Chapter 1
GL 2012 Page 2–5

Table 2.8 Steel grades to be used, depending on plate thickness and material class

Thickness t [mm] 1 > 15 > 20 > 25 > 30 > 35 > 40 > 50

Material class ≤ 15 ≤ 20 ≤ 25 ≤ 30 ≤ 35 ≤ 40 ≤ 50 ≤ 100 3
I A/AH A/AH A/AH A/AH B/AH B/AH D/DH D/DH 2
II A/AH A/AH B/AH D/DH D/DH 4 D/DH 4 E/EH E/EH
III A/AH B/AH D/DH D/DH 4 E/EH E/EH E/EH E/EH
1 Actual thickness of the structural member.
2 For thicknesses t > 60 mm E/EH.
3 For thicknesses > 100 mm the steel grade is to be agreed with GL.
4 For nominal yield stresses ReH ≥ 390 N/mm2 EH.

3.3 Material selection for local structural

For members not specifically mentioned normally
members
grade A/AH may be used. However, GL may require
3.3.1 The material selection for local structural also higher grades depending on the stress level.
members, which are not part of the longitudinal hull
structure, may in general be effected according to
new B.2.1
Table 2.9. For parts made of forged steel or cast steel 3.4 Material selection for structural members
C. is to be applied. which are exposed to low temperatures

new B.2.3.1 3.4.1 The material selection for structural mem-
bers, which are continuously exposed to temperatures
Table 2.9 Material selection for local structural below 0 °C, e.g. in or adjacent to refrigerated cargo
members holds, is governed by the design temperature of the
structural members. The design temperature is the
Structural member Material class temperature determined by means of a temperature
distribution calculation taking into account the design
hawse pipe, stern tube, pipe stan- environmental temperatures. The design environ-
I mental temperatures for unrestricted service are:
chion 3

hatch covers I air: + 5 °C

sea water: 0 °C
face plates and webs of girder
II 1
systems
new B.2.4.1
rudder body 2, rudder horn, sole
3.4.2 For ships intended to operate permanently in
piece, stern frame, propeller II
areas with low air temperatures (below and including
bracket, trunk pipe – 20 °C), e.g. regular service during winter seasons to
1
Arctic or Antarctic waters, the materials in exposed
Class I material sufficient, where rolled sections are used or
structures are to be selected based on the design tem-
the parts are machine cut from plates with condition on de-
livery of either "normalised", "rolled normalised" or "rolled perature tD, to be taken as defined in 3.4.5.
thermo-mechanical".
2
Materials in the various strength members above the
See 3.3.2.
lowest ballast water line (BWL) exposed to air are not
3 For pipe stanchions for cargo reefer holds Table 2.11 is ap- to be of lower grades than those corresponding to clas-
plicable. ses I, II and III, as given in Table 2.10, depending on
the categories of structural members (Secondary,
3.3.2 Rudder body plates, which are subjected to Primary and Special). For non-exposed structures and
stress concentrations (e.g. in way of lower support of structures below the lowest ballast water line, see 3.2
semi-spade rudders), are to be of class III material. and 3.3.

new footnote 2 of Table 2.9
new B.2.4.2

3.3.3 For topplates of machinery foundations lo- 3.4.3 The material grade requirements of each mate-
cated outside 0,6 L amidships, grade A ordinary hull rial class depending on thickness and design tempera-
structural steel may also be used for thicknesses above ture are defined in Table 2.11. For design temperatures
40 mm. tD < – 55 °C, materials are to be specially considered.

new B.2.3.2

new B.2.4.3
Chapter 1 Section 2 D Materials I - Part 1
Page 2–6 GL 2012

3.4.4 Single strakes required to be of class III or of
new B.3

grade E/EH or FH are to have breadths not less than
800 + 5 ⋅ L [mm], maximum 1 800 mm.
Plating materials for stern frames, rudder horns, rud- C. Forged Steel and Cast Steel
ders and shaft brackets are not to be of lower grades
than those corresponding to the material classes given Forged steel and cast steel for stem, stern frame, rudder
in 3.3. post as well as other structural components, which are

new B.2.4.4 subject of this Rule, are to comply with the GL Rules
for Metallic Materials (II-1). The tensile strength of
3.4.5 The design temperature tD is to be taken as forged steel and of cast steel is not to be less than 400
the lowest mean daily average air temperature in the N/mm2. While selecting forged steel and cast steel
area of operation, see Fig. 2.1. The following defini- toughness requirements and weldability shall be con-
tions apply: sidered beside the strength properties.
– Mean: statistical mean over an observation
new C
period of at least 20 years
– Average: average during one day and night
– Lowest: lowest during year D. Aluminium Alloys
For seasonally restricted service the lowest expected
value within the period of operation applies. 1. Where aluminium alloys, suitable for sea-

new B.2.4.5 water, as specified in the GL Rules for Materials and
Welding (II), are used for the construction of super-
structures, deckhouses, hatchway covers and similar
Mean daily maximum temperature parts, the conversion from steel to aluminium scant-
Mean daily average temperature lings is to be carried out by using the material factor:

635
k Aℓ =
R p0,2 + R m

For welded connections the respective values in

welded condition are to be taken. Where these figures
are not available, the respective values for the soft-
annealed condition are to be used.
Method of conversion:

− section modulus: WAℓ = WSt ⋅ k Aℓ

− plate thickness : t Aℓ = t St ⋅ k Aℓ

new D.1
MAR

MAY

AUG

NOV
OCT

DEC
APR
JAN

JUN
FEB

SEP
JUL

tD = design temperature 2. The smaller Young's modulus E is to be taken

into account when determining the buckling strength
Mean daily minimum temperature of structural elements subjected to compression. This
is to be applied accordingly to structural elements for
Fig. 2.1 Commonly used definitions of tempera- which maximum allowable deflections have to be
tures adhered to.

new D.2
4. Structural members which are stressed in
direction of their thickness
3. The conversion of the scantlings of the main
In case of high local stresses in the thickness direction, hull structural elements from steel into aluminium
e.g. due to shrinkage stresses in single bevel or double alloy is to be specially considered taking into account
bevel T-joints with a large volume of weld metal, the smaller Young's modulus E, as compared with
steels with guaranteed material properties in the thick- steel, and the fatigue strength aspects, specifically
ness direction according to the GL Rules for Steel and those of the welded connections.
Iron Materials (II-1-2), Section 1, I. are to be used.

new D.3
I - Part 1 Section 2 E Materials Chapter 1
GL 2012 Page 2–7

E. Austenitic Steels

Where austenitic steels are applied having a ratio

Rp0,2/Rm ≤ 0,5, after special approval the 1 % proof
stress Rp1,0 may be used for scantling purposes instead
of the 0,2 % proof stress Rp0,2.

new E
Chapter 1 Section 2 E Materials I - Part 1
Page 2–8 GL 2012

Table 2.10 Material classes and grades for structures exposed to low temperatures

Material class
Structural member category
Within 0,4 L Outside 0,4 L
amidships amidships

Secondary:
Deck plating exposed to weather, in general
I I
Side plating above BWL 5
Transverse bulkheads above BWL 5

Primary:
Strength deck plating 1
Continuous longitudinal members above strength deck, excluding II I
longitudinal hatch coamings
Longitudinal bulkhead above BWL 5

Top wing tank plating above BWL 5

Special:
Sheer strake at strength deck 2

Stringer plate in strength deck 2 III II

Deck strake at longitudinal bulkhead 3

Continuous longitudinal hatch coamings 4

1 Plating at corners of large hatch openings to be specially considered. Class III or grade E/EH to be applied in positions where high local
stresses may occur.
2 Not to be less than grade E/EH within 0,4 L amidships in ships with length exceeding 250 metres.
3 In ships with breadth exceeding 70 metres at least three deck strakes to be of class III.
4 Not to be less than grade D/DH
5 BWL = ballast water line.
I - Part 1 Section 2 E Materials Chapter 1
GL 2012 Page 2–9

Table 2.11 Material grade requirements for classes I, II and III at low temperature

Class I

tD tD tD tD
Plate thickness – 20 °C to – 25 °C – 26 °C to – 35 °C – 36 °C to – 45 °C – 46 °C to – 55 °C
[mm] normal higher normal higher normal higher normal higher
strength strength strength strength strength strength strength strength
t ≤ 10 A AH B AH D DH D DH
10 < t ≤ 15 B AH D DH D DH D DH
15 < t ≤ 20 B AH D DH D DH E EH
20 < t ≤ 25 D DH D DH D DH E EH
25 < t ≤ 30 D DH D DH E EH E EH
30 < t ≤ 35 D DH D DH E EH E EH
35 < t ≤ 45 D DH E EH E EH FH
45 < t ≤ 50 E EH E EH FH FH

Class II

tD tD tD tD
Plate thickness – 20 °C to – 25 °C – 26 °C to – 35 °C – 36 °C to – 45 °C – 46 °C to – 55 °C
[mm] normal higher normal higher normal higher normal higher
strength strength strength strength strength strength strength strength
t ≤ 10 B AH D DH D DH E EH
10 < t ≤ 20 D DH D DH E EH E EH
20 < t ≤ 30 D DH E EH E EH FH
30 < t ≤ 40 E EH E EH FH FH
40 < t ≤ 45 E EH FH FH
45 < t ≤ 50 E EH FH FH

Class III

tD tD tD tD
Plate thickness – 20 °C to – 25 °C – 26 °C to – 35 °C – 36 °C to – 45 °C – 46 °C to – 55 °C
[mm] normal higher normal higher normal higher normal higher
strength strength strength strength strength strength strength strength
t ≤ 10 D DH D DH E EH E EH
10 < t ≤ 20 D DH E EH E EH FH
20 < t ≤ 25 E EH E EH FH FH
25 < t ≤ 30 E EH E EH FH FH
30 < t ≤ 35 E EH FH FH
35 < t ≤ 40 E EH FH FH
40 < t ≤ 50 FH FH
I - Part 1 Section 3 A Design Principles Chapter 1
GL 2013 Page 3–1

Section 3

Design Principles

A. General
Furthermore, with asymmetric profiles where addi-
tional stresses occur according to L. the required sec-
1. Scope tion modulus is to be increased by the factor ksp de-
pending on the type of profile, see L.
This Section contains definitions and general design
criteria for hull structural elements as well as indica-
new B.3.1.5
tions concerning structural details.

new A.1 3. Plate panels subjected to lateral pressure
The formulae for plate panels subjected to lateral
2. Permissible stresses and required sectional pressure as given in the following Sections are based
properties on the assumption of an uncurved plate panel having
an aspect ratio b/a ≥ 2,24.
In the following Sections permissible stresses have
been stated in addition to the formulae for calculat- For curved plate panels and/or plate panels having
ing the section moduli and cross sectional areas of aspect ratios smaller than b/a ≈ 2,24, the thickness
webs of frames, beams, girders, stiffeners etc. and may be reduced as follows:
may be used when determining the scantlings of
those elements by means of direct strength calcula- t = C ⋅ a p ⋅ k f1 ⋅ f 2 + t K
tions.

new A.5 C = constant, e.g. C = 1,1 for tank plating
The required section moduli and web areas are related a
on principle to an axis which is parallel to the con- f1 = 1 − ≥ 0, 75
2r
nected plating.

new B.3.1.1 2
a
f2 = 1,1 − 0,5   ≤ 1, 0
For profiles usual in the trade and connected vertically b
to the plating in general the appertaining sectional
properties are given in tables. r = radius of curvature

new B.3.1.2 a = smaller breadth of plate panel

Where webs of stiffeners and girders are not fitted b = larger breadth of plate panel
vertically to the plating (e.g. frames on the shell in p = applicable design load
the flaring fore body) the sectional properties (mo-
ment of inertia, section modulus and shear area) have tK = corrosion addition according to K.
to be determined for an axis which is parallel to the
plating. The above does not apply to plate panels subjected to
ice pressure according to Section 15 and to longitudi-

new B.3.1.3 nally framed shell plating according to Section 6.
For bulb profiles and flat bars the section modulus
new B.2.2
of the inclined profile including plating can be calcu-
lated simply by multiplying the corresponding value 4. Stiffeners loaded by lateral pressure
for the vertically arranged profile by sinα where α
is the smaller angle between web and attached plating. If stiffened plate panels are loaded by lateral pressure,
the load is transmitted partly direct and partly by

new B.3.1.4 the stiffeners to the girders. The corresponding load
distribution on the stiffeners is reflected by the fac-
Note tor ma:
For bulb profiles and flat bars α in general needs only
be taken into account where α is less than 75°.

newB.3 Note
Chapter 1 Section 3 C Design Principles I - Part 1
Page 3–2 GL 2013

C. Unsupported Span
a  a 
2
a
m a = 0, 204  4 −    , with ≤ 1
ℓ  ℓ  ℓ
  1. Stiffeners, frames

new B.3.2 The unsupported span ℓ is the true length of the stiff-
eners between two supporting girders or else their
length including end attachments (brackets).
5. Fatigue strength
The frame spacings and spans are normally assumed
Where a fatigue strength analysis is required or will to be measured in a vertical plane parallel to the cen-
be carried out for structures or structural details this treline of the ship. However, if the ship's side deviates
shall be in accordance with the requirements of Sec- more than 10° from this plane, the frame distances and
tion 20. spans shall be measured along the side of the ship.

new A.4 Instead of the true length of curved frames the length
of the chord between the supporting points can be
selected.

new A.3
B. Upper and Lower Hull Flange
Shortening of the unsupported span due to brackets
1. All continuous longitudinal structural mem- and heel stiffeners is reflected by the factor mK:
bers up to zo below the strength deck at side and up to
zu above base line are considered to be the upper and ℓ KI + ℓ KJ
mK = 1−
lower hull flange respectively. 103 ⋅ ℓ

new B.1.1
ℓKI,ℓKJ= effective supporting length [mm] due to heel
stiffeners and brackets at frame I and J (see
2. Where the upper and/or the lower hull flange
are made from normal strength hull structural steel Fig. 3.1)
their vertical extent zo = zu equals 0,1 H.
1
ℓK = h s + 0,3 ⋅ h b + ≤ (ℓ b + h s )
On ships with continuous longitudinal structural mem- c1
bers above the strength deck a fictitious depth
H' = eB + e'D is to be applied.
1 c (ℓ − 0,3 ⋅ h b )  1 
c1 = + 2 b 2  mm 
eB = distance between neutral axis of the midship ℓ b − 0,3 ⋅ h b he  
section and base line [m]
e 'D = see Section 5, C.4.1 1
For ℓb ≤ 0,3 ⋅ hb, = 0 is to be taken.

new B.1.2 c1

hs, ℓb, hb, he see Fig. 3.1

3. The vertical extent z of the upper and lower
hull flange respectively made from higher tensile steel
of one quality is not to be less than: hs = height of the heel stiffener [mm]

z = e (1 − n ⋅ k) ℓb, hb = dimensions of the brackets [mm]

e = distance of deck at side or of the base line c2 = 3 in general

from the neutral axis of the midship section.
For ships with continuous longitudinal struc- c2 = 1 for flanged brackets
tural members above the strength deck, see (see Fig. 3.1 (c))
Section 5, C.4.1
n = W(a)/W he = height of bracket [mm] in the distance
xℓ = hs + 0,3 ⋅ hb of frame I and J respectively
W(a) = actual deck or bottom section modulus
W = Rule deck or bottom section modulus If no heel stiffeners or brackets are arranged the re-
1
Where two different steel grades are used it has to be spective values are to be taken as (hs, hb, ) = 0
observed that at no point the stresses are higher than c1
the permissible stresses according to Section 5, C.1. (see Fig. 3.1 (d)).

newB.1.3
new B.3.3.1
I - Part 1 Section 3 C Design Principles Chapter 1
GL 2013 Page 3–3

2. Corrugated bulkhead elements

The unsupported span ℓ of corrugated bulkhead ele-

ments is their length between bottom or deck and their
length between vertical or horizontal girders. Where
corrugated bulkhead elements are connected to box
type elements of comparatively low rigidity, their
depth is to be included into the span ℓ unless other-
wise proved by calculations.

new A.3

(a) (b)

b b

c c

hb hb
he he c
tb c tb

A B B A
hp

0,3 × hb 0,3 × hb
hs

K K

x x

Frame I 2 × tb ³ c £ 25 mm Frame J

0,3 × hb

K= 0
A=B

A B A

c
tb
he
hb

(c) (d)

Fig. 3.1 End attachment

Chapter 1 Section 3 D Design Principles I - Part 1
Page 3–4 GL 2013

3. Transverses and girders tK = corrosion addition according to K.

The unsupported span ℓ of transverses and girders is to W = section modulus of smaller section [cm3]
be determined according to Fig. 3.2, depending on the
tmin = 5,0 + tK [mm]
type of end attachment.
In special cases, the rigidity of the adjoining girders is tmax = web thickness of smaller section
to be taken into account when determining the span of
For minimum thicknesses in tanks and in cargo holds
girder.
of bulk carriers see Section 12, A.7., Section 23, B.5.3

new B.3.3.2 and Section 24, A.13.

new B.3.5.2.2
c =a+b
4 2.3 The arm length of brackets is not to be less
than:
W
b'

a a' ℓ = 46, 2 ⋅ 3 ⋅ k 2 ⋅ ct
b = b'
b
b

c k1
c
ℓ = 100 mm
a
a a'
t
ct =
Fig. 3.2 Unsupported span ℓ ta
ta = "as built" thickness of bracket [mm]
≥ t according to 2.2
D. End Attachments
W = see 2.2
1. Definitions k2 = material factor k for the bracket, according to
Section 2, B.2.
For determining scantlings of beams, stiffeners and
girders the terms "constraint" and "simple support" The arm length ℓ is the length of the welded connection.
will be used.

new B.3.5.2.3
"Constraint" will be assumed where for instance the
stiffeners are rigidly connected to other members by Note
means of brackets or are running throughout over For deviating arm length the thickness of brackets is
supporting girders.
to be estimated by direct calculations considering
"Simple support" will be assumed where for instance sufficient safety against buckling.
the stiffener ends are sniped or the stiffeners are con-

new B.3.5.2.3 Note
nected to plating only, see also 3.

new B.3.5.1 2.4 The throat thickness a of the welded connec-
tion is to be determined according to Section 19,
C.2.7.
2. Brackets

new B.3.5.2.4
2.1 For the scantlings of brackets the required
section modulus of the section is decisive. Where 2.5 Where flanged brackets are used the width of
sections of different section moduli are connected to flange is to be determined according to the following
each other, the scantlings of the brackets are generally formula:
governed by the smaller section.
W

new B.3.5.2.1 b = 40 + [mm]
30
2.2 The thickness of brackets is not to be less b is not to be taken less than 50 mm and need not be
than: taken greater than 90 mm.
W
new B.3.5.2.5
t = c ⋅ 3 + tK [mm]
k1
3. Sniped ends of stiffeners
c = 1,2 for non-flanged brackets Stiffeners may be sniped at the ends, if the thickness
= 0,95 for flanged brackets of the plating supported by stiffeners is not less than:
k1 = material factor k for the section, according to
Section 2, B.2.
I - Part 1 Section 3 F Design Principles Chapter 1
GL 2013 Page 3–5

p ⋅ a (ℓ − 0,5 ⋅ a) 2.2 The effective cross sectional area of plates is not

t = c [mm] to be less than the cross sectional area of the face plate.
R eH

new C.2.2
p = design load [kN/m2]
2.3 The effective width of stiffeners and girders
ℓ = unsupported length of stiffener [m] subjected to compressive stresses may be determined
according to F.2.2, but is in no case to be taken greater
a = spacing of stiffeners [m] than the effective breadth determined by 2.1.
c = 15,8 for watertight bulkheads and for tank

new C.2.3
bulkheads when loaded by p2 accord-
ing to Section 4, D.1.2
3. Cantilevers
= 19,6 otherwise
Where cantilevers are fitted at every frame, the effec-

new B.2.3 tive breadth of plating may be taken as the frame spac-
ing. Where cantilevers are fitted at a greater spacing
4. Corrugated bulkhead elements the effective breadth of plating at the respective cross
section may approximately be taken as the distance of
Care is to be taken that the forces acting at the sup- the cross section from the point on which the load is
ports of corrugated bulkheads are properly transmitted acting, however, not greater than the spacing of the
into the adjacent structure by fitting structural ele- cantilevers.
ments such as carlings, girders or floors in line with
the corrugations.
new C.3

new B.4.1
Table 3.1 Effective breadth em of frames and
Note girders
Where carlings or similar elements cannot be fitted in
ℓ/e 0 1 2 3 4 5 6 7 ≥8
line with the web strips of corrugated bulkhead ele-
ments, these web strips cannot be included into the em1/e 0 0,36 0,64 0,82 0,91 0,96 0,98 1,00 1,0
section modulus at the support point for transmitting
the moment of constraint. em2/e 0 0,20 0,37 0,52 0,65 0,75 0,84 0,89 0,9

Deviating from the formula stipulated in Section 11, em1 is to be applied where girders are loaded by uni-
B.4.3 the section modulus of a corrugated element is formly distributed loads or else by not less than 6
then to be determined by the following formula: equally spaced single loads.
em2 is to be applied where girders are loaded by 3 or
W = t ⋅ b (d + t) [cm3] less single loads.

new B.4.1 Note Intermediate values may be obtained by direct inter-
polation.
ℓ = length between zero-points of bending moment
curve, i.e. unsupported span in case of simply
supported girders and 0,6 × unsupported span in
E. Effective Breadth of Plating
case of constraint of both ends of girder
e = width of plating supported, measured from centre
1. Frames and stiffeners
to centre of the adjacent unsupported fields
Generally, the spacing of frames and stiffeners may be
taken as effective breadth of plating.

new C.1
F. Proof of Buckling Strength

2. Girders The calculation method is based on DIN-standard 18800.

new D
2.1 The effective breadth of plating em of frames
and girders may be determined according to Table 3.1 1. Definitions
considering the type of loading.
a = length of single or partial plate field [mm]
Special calculations may be required for determining
the effective breadth of one-sided or non-symmetrical b = breadth of single plate field [mm]
flanges. α = aspect ratio of single plate field

new C.2.1 = a/b
Chapter 1 Section 3 F Design Principles I - Part 1
Page 3–6 GL 2013

n = number of single plate field breadths within
new D.2 Note

the partial or total plate field
ψ = edge stress ratio according to Table 3.3
t = nominal plate thickness [mm]
= ta – tK [mm] F1 = correction factor for boundary condition at
the long. stiffeners according to Table 3.2
ta = plate thickness as built [mm]
tK = corrosion addition according to K. [mm] σe = reference stress
2

new A.3 t
= 0,9 ⋅ E   [N / mm 2 ]
b
long. stiffener single field partial field
S = safety factor
= 1,1 in general
n·b = 1,2 for structures which are exclusively
am exposed to local loads
bm

bb

y
= 1,05 for combinations of statistically inde-
a pendent loads

y Table 3.2 Correction factor F1

x
transverse stiffener 1,0 for stiffeners sniped at both ends
longitudinal : stiffener in the direction of the length a Guidance values where both ends are effectively
transverse : stiffener in the direction of the breath b connected to adjacent structures * :
1,05 for flat bars
Fig. 3.3 Definition of plate fields subject to buckling 1,10 for bulb sections
σx = membrane stress in x-direction [N/mm2] 1,20 for angle and tee-sections
1,30 for girders of high rigidity
σy = membrane stress in y-direction [N/mm2] (e.g. bottom transverses)
τ = shear stress in the x-y plane [N/mm2] * Exact values may be determined by direct calcula tions.

Compressive and shear stresses are to be taken posi-

tive, tension stresses are to be taken negative. For constructions of aluminium alloys the safety fac-
tors are to be increased in each case by 0,1.

new D.2
λ = reference degree of slenderness
Note
R eH
If the stresses in the x- and y-direction contain already =
the Poisson effect, the following modified stress values K ⋅ σe
may be used:
K = buckling factor according to Tables 3.3 and 3.4
Both stresses σx* und σy* are to be compressive stres-
ses, in order to apply the stress reduction according to
new D.2
the following formulae: In general, the ratio plate field breadth to plate thick-
ness shall not exceed b/t = 100.
(
σ x = σ *x − 0,3 ⋅ σ *y ) 0,91
new D.3.3
σy = (σ *
y − 0,3 ⋅ σ *x ) 0,91
2. Proof of single plate fields
σx*, σy* = stresses containing the Poisson effect
2.1 Proof is to be provided that the following con-
Where compressive stress fulfils the condition σy* < 0,3⋅ σx*, dition is complied with for the single plate field a ⋅ b:
then σy = 0 and σx = σx*.
2 e
 σx ⋅ S  1  σy ⋅ S 
e
 σx ⋅ σy ⋅ S2 
Where compressive stress fulfils the condition σx*< 0,3⋅ σy*,   +   − B 
then σx = 0 and σy = σy*.  κx ⋅ ReH   κy ⋅ ReH   ReH2 
   
e
When at least σx* or σy* is tension stress, then σx = σx*  τ ⋅ S ⋅ 3 3
and σy = σy*. +   ≤ 1,0
 κτ ⋅ ReH 
 
I - Part 1 Section 3 F Design Principles Chapter 1
GL 2013 Page 3–7

2.2 Effective width of plating

Each term of the above condition shall not exceed 1,0.
The reduction factors κx, κy and κτ are given in Table
3.3 and/or 3.4.
The effective width of plating may be determined by
Where σx ≤ 0 (tension stress), κx = 1,0. the following formulae:
Where σy ≤ 0 (tension stress), κy = 1,0.
The exponents e1, e2 and e3 as well as the factor B are
calculated or set respectively: bm = κx ⋅ b for longitudinal stiffeners

new D.3.1

Exponents e1 – e3 plate field am = κy ⋅ a for transverse stiffeners

and factor B plane curved
e1 1+ κ 4x 1,25
e2 1+ κ 4y 1,25 see also Fig. 3.3.
2
e3 1 + κ x ⋅ κ y ⋅ κτ 2,0
B
5
σx and σy positive ( κx ⋅ κy ) 0 The effective width of plating is not to be taken
greater than the effective breadth obtained from E.2.1.
(compression stress)
B
σx or σy negative 1 ––
(tension stress)
new D.3.2
Chapter 1 Section 3 F Design Principles I - Part 1
Page 3–8 GL 2013

Table 3.3 Plane plate fields

Edge stress Aspect ratio

Load case Buckling factor K Reduction factor k
ratio y a
1 8,4 kx = 1 for l £ lc
1³y³0 K =
y + 1,1 1 0,22
kx = c - for l > lc
sx sx l l2
0>y>–1 a>1 K = 7,63 – y (6,26 – 10 y)
t c = (1,25 - 0,12y) £ 1,25
b

y·sx y·sx c
a·b y£–1
2
K = (1 – y) · 5,975 lc = 2 1 + Ö 1- 0,88
c

2 1 R+F2 (H-R)
ky = c -
1 2 2,1 l l2
1³y ³ 0 a³1 K = F1 1 +
sy y·sy a2 (y+1,1) c = (1,25 - 0,12y) £ 1,25
t
b

1 2
2,1 (1+y) R = l 1- l for l < lc
sy 0>y >–1 1 £ a £ 1,5 K = F1 1 +
y·sy a2
1,1 c
a·b
y R = 0,22 for l ³ lc
– 2 (13,9 – 10 y)
a c
lc = 1 + Ö 1- 0,88
2 c
1 2 2,1 (1+y)
a > 1,5 K = F1 1 + 2
a 1,1 K -1
F = 1- 0,91 c1 ³ 0
y 2 2
– (5,87 + 1,87 a l
a2 p

8,6 l2p = l2 - 0,5 1 £ lp2 £ 3

+ 2 – 10 y)
a c1 = 1 for sy due to
direct loads
3 (1-y) 1-y 2
y£ –1 1£a£ K = F1 5,975 F1
4 a c1 = 1 - ³ 0 for sy
a
due to bending (in general)

3 (1-y) 1-y 2 c1 = 0 for sy due to bending

a> K = F1 3,9675
4 a in extreme load cases
(e. g. w. t. bulkheads)
1-y 4
+ 0,5375 2l
a H =l- ³R
c (T+Ö T2 - 4 )
+ 1,87 14 1
T =l+ +
15l 3
3 4 (0,425 + 1/a2)
1 ³y³0 K =
3y+1
sx sx
a>0
t 1
b

K = 4 0,425 + (1 + y)
0 >y³–1 a2 kx = 1 for l £ 0,7
y·sx a·b y·sx
– 5 · y (1 – 3,42 y)
4 1
kx = for l > 0,7
y·sx y·sx l2 + 0,51
1 ³y³–1 1 3-y
a>0 K = 0,425 +
t a2 2
b

sx sx
a·b
I - Part 1 Section 3 F Design Principles Chapter 1
GL 2013 Page 3–9

Table 3.3 Plane plate fields (continued)

Edge stress Aspect ratio

Load case Buckling factor K Reduction factor k
ratio y a
5 K = Kt · 3
t

t t t a³1 Kt = 5,34 + 42
b

a
t
a·b 5,34
0<a < 1 Kt = 4 + kt = 1 for l £ 0,84
a2
0,84
6 K = K' × r kt = for l > 0,84
l
da K' = K according to load case 5
t r = Reduction factor
da d
db

)(1 - b )
b

t r = (1 -
a b
t t da db
t with £ 0,7 and £ 0,7
a·b a b

7
kx = 1 for l £ 0,7
sx sx a ³ 1,64 K = 1,28
1
kx =
b

t
1 l2 + 0,51
a·b a < 1,64 K = 2 + 0,56 + 0,13 a2
a for l > 0,7
8
a ³ 2 K = 6,97
sx sx 3
t
b

2 1
a < K = + 2,5 + 5 a2
a·b 3 a2
kx = 1 for l £ 0,83
9
a ³ 4 K = 4
sx sx
4–a 4 1 0,22
t 4 > a > 1 K = 4+ 2,74 kx = 1,13 -
b

3 l l2
a·b 4 for l > 0,83
a £ 1 K = 2 + 2,07 + 0,67 a2
a
10 K = 6,97
a ³ 4
sx sx
4–a 4
t 4 > a > 1 K = 6,97 + 3,1
b

3
a·b 4
a £ 1 K = + 2,07 + 4 a2
a2
Explanations for boundary conditions plate edge free
plate edge simply supported
plate edge clamped
Chapter 1 Section 3 F Design Principles I - Part 1
Page 3–10 GL 2013

Table 3.4 Curved plate field R/t ≤ 2500 1

Aspect ratio
Load case Buckling factor K Reduction factor k
b/R

1a
b
sx
kx = 1 2
b (R · t) 0,175
b R for l £ 0,4
£ 1,63 K = +3
R
R t R·t b0,35
t
kx = 1,274 – 0,686 l
1b sx
for 0,4 < l £ 1,2
b with
pe · R
sx = 0,65
t
b2 R2 2 kx =
b
> 1,63
R K = 0,3 + 2,25 l2
R 2
t R t R b·t for l > 1,2
pe

pe = external pressure in
[N/mm2]

2 ky = 1 2

for l £ 0,25
b R 2 b2
b £ 0,5 K = 1+
R t 3 R·t ky = 1,233 – 0,933 l
sy for 0,25 < l £ 1
R b R b2 b t
> 0,5 K = 0,267 3– ky = 0,3 / l3
t R t R·t R R
for 1 < l £ 1,5
sy
b2
³ 0,4 ky = 0,2 / l2
R·t
for l > 1,5
3
b b R 0,6 · b R·t R·t
£ K = + – 0,3
sx R t R·t b b2
as in load case 1a
R b R b2 R2 2
t > K = 0,3 2
+ 0,291
R t R b·t
sx
4 kt = 1
K = Kt × 3
b for l £ 0,4
b R 0,67 · b3 0,5
£ 8,7 Kt = 28,3 + kt = 1,274 – 0,686 l
t R t R1,5 · t1,5
R
t
for 0,4 < l £ 1,2
b R b 2 0,65
> 8,7 Kt = 0,28 kt =
R t R R·t l2
for l > 1,2
Explanations for boundary conditions: plate edge free
plate edge simply supported
plate edge clamped
1 For curved plate fields with a very large radius the k-value need not to be taken less than one derived for the expanded plane field.

2 For curved single fields. e.g. the bilge strake, which are located within plane partial or total fields, the reduction factor k may taken
as follow:
2 2
Load case 1b: kx = 0,8/l £ 1,0: load case 2: ky = 0,65/l £ 1,0
I - Part 1 Section 3 F Design Principles Chapter 1
GL 2013 Page 3–11

Note a ≥ em
The effective width e'm of stiffened flange plates of e'm = n ⋅ am < em
girders may be determined as follows:
em
Stiffening parallel to web of girder: n = 2,7 ⋅ ≤ 1
a
e e = width of plating supported according to E.2.1
em
For b ≥ em or a < em respectively, b and a have to be
em' exchanged.
am and bm for flange plates are in general to be de-
termined for ψ = 1.
Stress distribution between two girders:

 y y 
σx ( y)= σ x1 ⋅ 1− 3 + c1 − 4 ⋅ c2 − 2 ( 1+ c1 − 2 c2 )
sx,em'(y)

sx,em(y)

 e e 

σ x2
c1 = 0 ≤ c1 ≤ 1
σ x1
bm bm
1,5
c2 = ⋅ e"m1 + e"m2 − 0,5
( )
e
e'm1
b b b b e"m1 =
em1

e'm2
y e"m2 =
em2
b < em σx1, σx2 = normal stresses in flange plates of adja-
e'm = n ⋅ bm cent girder 1 and 2 with spacing e
y = distance of considered location from
n = integer number of the stiffener spacing b girder 1
inside the effective breadth em according to
Table 3.1 Scantlings of plates and stiffeners are in general to be
determined according to the maximum stresses σx(y)
e  at girder webs and stiffeners respectively. For stiffen-
= int  m 
 b  ers under compression arranged parallel to the girder
web with spacing b no lesser value than 0,25 ⋅ ReH
Stiffening perpendicular to web of girder: shall be inserted for σx(y=b).
Shear stress distribution in the flange plates may be
e e
assumed linearly.
em
em '
new D.3.3 Note

2.3 Webs and flanges

sx1

sx(y)

For non-stiffened webs and flanges of sections and

sx2

girders proof of sufficient buckling strength as for

am
single plate fields is to be provided according to 2.1.

new D.3.4
a Note
Within 0,6 L amidships the following guidance values
are recommended for the ratio web depth to web
y thickness and/or flange breadth to flange thickness:
Chapter 1 Section 3 F Design Principles I - Part 1
Page 3–12 GL 2013

hw for transverse stiffeners:

flat bars : ≤ 19,5 k
tw 2
p ⋅ a ( n ⋅ b)
= [N ⋅ mm]
angle, tee and bulb sections: cs ⋅ 8 ⋅ 103
hw
web : ≤ 60,0 k p = lateral load [kN/m²] according to Section 4
tw
FKi = ideal buckling force of the stiffener [N]
bi
flange : ≤ 19,5 k π2
tf FKix = 2
E ⋅ I x ⋅ 104 for long. stiffeners
a
bi = b1 or b2 according to Fig. 3.4,
π2
the larger value is to be taken. FKiy = 2
⋅ E ⋅ I y ⋅ 104 for transv. stiffeners

new D.3.4 Note (n ⋅ b)
Ix, Iy = moments of inertia of the longitudinal or
3. Proof of partial and total fields transverse stiffener including effective width
of plating according to 2.2 [cm4]
3.1 Longitudinal and transverse stiffeners
b ⋅ t3
Proof is to be provided that the continuous longitudi- Ix ≥
nal and transverse stiffeners of partial and total plate 12 ⋅ 104
fields comply with the conditions set out in 3.2 and
3.3. a ⋅ t3
Iy ≥

new D.4.1 12 ⋅ 104

3.2 Lateral buckling pz = nominal lateral load of the stiffener due to σx,
σy and τ [N/mm2]
σa + σ b
S≤ 1 for longitudinal stiffeners:
R eH
ta   π ⋅ b  
2
pzx = σx1  + 2 ⋅ cy ⋅ σy + 2 τ1 
b   a 
σa = uniformly distributed compressive stress in

the direction of the stiffener axis [N/mm²]  
= σx for longitudinal stiffeners for transverse stiffeners:

ta  
= σy for transverse stiffeners 2
   Ay 
pzy = 2 ⋅ cx ⋅σx1 + σy π ⋅ a 1 + + 2 τ1
σb = bending stress in the stiffeners a  n ⋅ b  a ⋅ ta  
 
M o + M1
= [N / mm 2 ]  Ax 
Wst ⋅ 10 3 σx1 = σx  1 + 
 b ⋅ ta 
Mo = bending moment due to deformation w of cx, cy = factor taking into account the stresses vertical
stiffener to the stiffener's axis and distributed variable
pz ⋅ w along the stiffener's length
= FKi [N ⋅ mm]
cf − p z = 0,5 (1 + ψ ) for 0 ≤ ψ ≤ 1

( cf − pz ) > 0 0,5
= for ψ < 0
1 − ψ
M1 = bending moment due to the lateral load p
for continuous longitudinal stiffeners: ψ = edge stress ratio according to Table 3.3

p ⋅ b ⋅ a2 Ax,Ay= sectional area of the longitudinal or trans-

= 3
[N ⋅ mm] verse stiffener respectively [mm2]
24 ⋅ 10
 m m 
τ1 = τ − t R eH ⋅ E  1 + 2  ≥ 0
2
 a b2  
I - Part 1 Section 3 F Design Principles Chapter 1
GL 2013 Page 3–13

for longitudinal stiffeners: 2

 a 2 b
cxα =  +  for a ≥ 2 b
a
≥ 2, 0 : m1 = 1, 47 m 2 = 0, 49 2 b a 
b
2
a   a  
2
< 2, 0 : m1 = 1,96 m 2 = 0,37 
= 1 +    for a < 2 b
b   2 b 
 
for transverse stiffeners:
π2
a
≥ 0,5 : m1 = 0,37 m2 =
1,96 cfy = cs ⋅ FKiy ⋅ 2 (
⋅ 1 + cpy )
n ⋅ b n 2 (n ⋅ b)
for transv. stiffeners
a 1, 47
< 0,5 : m1 = 0, 49 m2 = cs = factor accounting for the boundary conditions
n ⋅ b n2
of the transverse stiffener
w = wo + w1 = 1,0 for simply supported stiffeners
wo = assumed imperfection [mm] = 2,0 for partially constraint stiffeners
a b 1
≥ w ox ≤ for long. stiffeners cpy =
250 250
0,91  12 ⋅ 10 ⋅ I y 
4

n⋅b a 1 + ⋅  − 1
≥ w oy ≤ for transv. stiffeners c yα  3
t ⋅ a 
 
250 250
2
however wo ≤ 10 mm n ⋅ b 2a 
cyα =  +  for n⋅b≥2a
 2 a n ⋅ b
Note
2
For stiffeners sniped at both ends wo shall not be  n ⋅ b 
2

taken less than the distance from the midpoint of plat- = 1 +    for n⋅b<2a
  2 a  
ing to the neutral axis of the profile including effective  
width of plating. Wst = section modulus of stiffener (long. or trans-

Note changed into a requirement verse) [cm3] including effective width of plat-
ing according to 2.2
w1 = deformation of stiffener due to lateral load p
at midpoint of stiffener span [mm] If no lateral load p is acting the bending stress σb is to
be calculated at the midpoint of the stiffener span for
In case of uniformly distributed load the following
that fibre which results in the largest stress value. If a
values for w1 may be used:
lateral load p is acting, the stress calculation is to be
for longitudinal stiffeners: carried out for both fibres of the stiffener's cross sec-
tional area (if necessary for the biaxial stress field at
p ⋅ b ⋅ a4
w1 = the plating side).
384 ⋅ 107 ⋅ E ⋅ I x

new D.4.2
for transverse stiffeners:
4
Note
5 ⋅ a ⋅ p (n ⋅ b)
w1 = Longitudinal and transverse stiffeners not subjected to
384 ⋅ 107 ⋅ E ⋅ I y ⋅ cs2 lateral load p have sufficient scantlings if their mo-
ments of inertia Ix and Iy are not less than obtained by
cf = elastic support provided by the stiffener the following formulae:
[N/mm2]
 
π2 pzx ⋅ a2  wox ⋅ hw a2 
cfx = FKix ⋅
a2
(
⋅ 1 + cpx ) for long. stiffeners Ix = 2  + 2  [cm4]
π ⋅ 104  ReH − σ π ⋅ E
 x 
1  S 
cpx =
0,91  12 ⋅ 104 ⋅ I x 
1 + ⋅  − 1   
 t3 ⋅ b 2
c xα   pzy ⋅ ( n ⋅ b)  woy ⋅ hw ( n ⋅ b)2  [cm4]
Iy =  + 2 
π 2 ⋅ 104  ReH − σ π ⋅E
 y 
 S 
Chapter 1 Section 3 F Design Principles I - Part 1
Page 3–14 GL 2013

new D.4.2 Note IP = polar moment of inertia of the stiffener re-

lated to the point C [cm4]
3.3 Torsional buckling
IT = St. Venant's moment of inertia of the stiffener
3.3.1 Longitudinal stiffeners [cm4]
σx ⋅ S
≤ 1, 0 Iω = sectorial moment of inertia of the stiffener
κT ⋅ R eH
related to the point C [cm6]
κT = 1,0 for λT ≤ 0,2
ε = degree of fixation
1
= for λ T > 0, 2
φ + φ2 − λ T2 a4
= 1 + 10− 4
b 4 hw 
= 0,5 1 + 0, 21 ( λ T − 0, 2 ) + λ T2
( ) Iω  3 + 
φ t 3 t w3
 
λT = reference degree of slenderness
hw = web height [mm]
R eH
=
σKiT tw = web thickness [mm]

E  π2 ⋅ Iω ⋅ 102  bf = flange breadth [mm]

σKiT =  ε + 0,385 ⋅ IT  [N/mm2]
IP a 2 
  tf = flange thickness [mm]
For IP, IT, Iω see Fig. 3.4 and Table 3.5.
Aw = web area hw ⋅ t w
bf bf bf
Af = flange area bf ⋅ tf
tf

tw tw tw tw
new D.4.3.1
hw

ef

b1 b1 b2
3.3.2 Transverse stiffeners
C C C C
ta

For transverse stiffeners loaded by compressive

ef = hw + tf / 2 stresses and which are not supported by longitudinal
stiffeners, proof is to be provided in accordance with
Fig. 3.4 Main dimensions of typical longitudinal
3.3.1 analogously.
stiffeners

newD.4.3.2

Table 3.5 Formulas for the calculation of moments of inertia IP, IT and Iω

Section IP IT Iω

h 3w ⋅ t w h w ⋅ t 3w  t  h 3w ⋅ t 3w
Flat bar 4 
1 − 0, 63 w 
3 ⋅ 104 3 ⋅ 10  hw  36 ⋅ 106

for bulb and angle sections:

h w ⋅ t 3w  t  Af ⋅ ef2 ⋅ bf2  Af + 2,6 Aw 

4 
1 − 0, 63 w   
Sections with 3 ⋅ 10  h w  12 ⋅ 106  Af + Aw 
 Aw ⋅ h w
2 
bulb or flange  + Af ⋅ ef2  10− 4
3  +
  for tee-sections:
bf ⋅ t 3f  tf  b3f ⋅ t f ⋅ ef2
4 1 − 0, 63 
3 ⋅ 10  bf 
12 ⋅ 106
I - Part 1 Section 3 H Design Principles Chapter 1
GL 2013 Page 3–15

G. Rigidity of Transverses and Girders 3. Transverses and girders

The moment of inertia of deck transverses and girders, 3.1 Where transverses and girders fitted in the
is not to be less than: same plane are connected to each other, major discon-
tinuities of strength shall be avoided. The web depth
I = c ⋅ W ⋅ ℓ [cm 4 ] of the smaller girder shall, in general, not be less than
60 % of the web depth of the greater one.
c = 4,0 if both ends are simply supported

new E.3.1
= 2,0 if one end is constrained
3.2 The taper between face plates with different
= 1,5 if both ends are constrained
dimensions is to be gradual. In general the taper shall
W = section modulus of the structural member not exceed 1 : 3. At intersections the forces acting in
considered [cm3] the face plates are to be properly transmitted.
ℓ = unsupported span of the structural member
new E.3.2
considered [m]
3.3 For transmitting the acting forces the face

new Section 10, B.2.2.1 plates are to be supported at their knuckles. For sup-
porting the face plates of cantilevers, see Fig. 3.5.

new E.3.3
H. Structural Details

1. General
Continuity of structure shall be maintained throughout
the length of the ship. Where significant changes in
structural arrangement occur adequate transitional
structure is to be provided.

new E.1.1

2. Longitudinal members
Fig. 3.5 Support of face plates of cantilevers
2.1 All longitudinal members taken into account
for calculating the midship section modulus are to 3.4 Upon special approval the stiffeners at the
extend over the required length amidships and are to knuckles may be omitted if the following condition is
be tapered gradually to the required end scantlings, see complied with:
also Section 5, C.1.
be

new E.2.1 σa ≤ σ p [N / mm 2 ]
bf
2.2 Abrupt discontinuities of strength of longitu- σa = actual stress in the face plate at the knuckle
dinal members are to be avoided as far as practicable. [N/mm2]
Where longitudinal members having different scant-
lings are connected with each other, smooth transi- σp = permissible stress in the face plate [N/mm²]
tions are to be provided.
bf = breadth of face plate [mm]
Special attention in this respect is to be paid to the
construction of continuous longitudinal hatch coam- be = effective breadth of face plate:
ings forming part of the longitudinal hull structure.
be = t w + n1 ( t f + c (b − t f ) ) [mm]

new E.2.2
tw = web thickness [mm]
2.3 At the ends of longitudinal bulkheads or
tf = face plate thickness [mm]
continuous longitudinal walls suitable scarping brack-
ets are to be provided. 1
b = (bf − t w ) [mm]

new E.2.3 n1
1 n3 ⋅ tf
c = 2
+
(b − tf ) (R ⋅ tf ) − n2 α2 ⋅ R

cmax = 1
Chapter 1 Section 3 H Design Principles I - Part 1
Page 3–16 GL 2013

2α = knuckle angle [°], see Fig. 3.6 d d d

= − 0,51 ⋅ 4 for 8 ≥ > 1,35
αmax = 45° tf tf tf
R = radius of rounded face plates [mm] d d
= 0,5 ⋅ + 0,125 for 1,35 ≥ ≥ − 0, 25
= tf for knuckled face plates tf tf
n1 = 1 for unsymmetrical face plates (face plate

1
tf
at one side only)
d

2a
sa

tf
= 2 for symmetrical face plates
n2 = 0 for face plates not supported by brackets

( b − t f )2
= 0,9 ⋅ ≤ 1, 0
R ⋅ tf (a) (b)
for face plates of multi-web girders
n3 = 3 if no radial stiffener is fitted
= 3 000 if two or more radial stiffeners are
2a

R
fitted or if one knuckle stiffener is fit-
ted according to (a) in Fig. 3.6 bf

4 b
d 

tf
=  − 8
t
 f  tw

h
tb
if one stiffener is fitted according to (b) in Fig.
3.6
3 ≤ n3 ≤ 3 000 Fig. 3.6 Typical stiffeners of rounded of knuckled
face plates
d = distance of the stiffener from the knuckle [mm]
For proof of fatigue strength of the weld seam in the The welding seam has to be shaped according to
knuckle, the stress concentration factor KS (angle 2 α Fig. 3.7.
according to Fig. 3.5 < 35°) related to the stress σa in
Scantlings of stiffeners (guidance):
the face plate of thickness tf may be estimated as fol-
lows and may be evaluated with case 5 of Section 20, σa
thickness: tb = t f ⋅ 2sin α
Table 20.3: σp
  height: h = 1,5 ⋅ b
 
tf  6 ⋅ n4  t f1 
new E.3.4
KS = 1 + 2
⋅ tan  ⋅ 2 α  
t f1   tf  R  3.5 For preventing the face plates from tripping
 1+  t  
  f1   adequately spaced stiffeners or tripping brackets are to
be provided. The spacing of these tripping elements
d shall not exceed 12 ⋅ bf.
n4 = 7,143 for >8
tf
new E.3.5
I - Part 1 Section 3 H Design Principles Chapter 1
GL 2013 Page 3–17

°
~ 40
* depending on the welding process
tf2

tf1

tf
1/3 ¸ 0,5 tf1

2a

tf
tf
0 ¸1

2¸(4)* 25 + £ d £ 50
2
tf ³ 15 mm ~ 40°

Fig. 3.7 Welding and support of knuckles

3.6 The webs are to be stiffened to prevent buck-
t
ling (see also F.). d = 25 + f
2

new E.3.6
but not more than 50 mm, see Fig. 3.7.
3.7 The location of lightening holes shall be such
new E.4.1
that the distance from hole edge to face plate is not
less than 0,3 × web depth. On bulk carriers at knuckles between inner bottom and
tank side slopes in way of floors the welding cut-outs

new.3.7 have to be closed by collar plates or insert plates, see
Fig. 3.8. In both cases a full penetration weld is re-
3.8 In way of high shear stresses lightening holes quired to inner bottom and bottom girder.
in the webs are to be avoided as far as possible.

new E.4.2

new E.3.8

3.9 In the fore and aft ship region the stiffness of A

Collar plate or insert plate
webframes and girders has to be sufficient to support with full penetration weld
connected structural parts like decks adequately. If connection to inner bottom, A
necessary, wing bulkheads have to be arranged, espe- hopper plating and bottom
cially in areas with high transverse loads e.g. due to girder
slamming pressures. Double
bottom

new E.3.9 floor
Section A - A
4. Knuckles (general)
Edge Floor
Flanged structural elements transmitting forces per- chamfered
pendicular to the knuckle are to be adequately sup- for full
ported at their knuckle, i.e. the knuckles of the inner penetration
bottom are to be located above floors, longitudinal
girders or bulkheads.
If longitudinal structures, such as longitudinal bulk-
heads or decks, include a knuckle which is formed by
two butt-welded plates, the knuckle is to be supported
in the vicinity of the joint rather than at the exact loca- Fig. 3.8 Knuckles of the double bottom
tion of the joint. The minimum distance d to the sup-
porting structure is to be at least
Chapter 1 Section 3 J Design Principles I - Part 1
Page 3–18 GL 2013

J. Evaluation of Notch Stress For some types of openings the notch factors Kt for
the calculation of the notch stress σK are given in
The notch stress σK evaluated for linear-elastic mate-
Figs. 3.9 and 3.10.
rial behaviour at free plate edges, e.g. at hatch corners,
openings in decks, walls, girders etc., should, in gen- They apply to stress conditions with uniaxial or biax-
eral, fulfill the following criterion: ial normal stresses.

σK ≤ f ⋅ R eH In case of superimposed stresses due to longitudinal

and shear loads, the maximum notch stress σKmax of
rectangular openings with rounded corners can ap-
f = 1,1 for normal strength hull structural steel
proximately be calculated as follows:
= 0,9 for higher strength hull structural steel
with ReH = 315 N/mm2 2
σKmax = + K tv ⋅ σ1 + 3 ⋅ τ1
2

= 0,8 for higher strength hull structural steel

with ReH = 355 N/mm2 for σ1 = tensile stress
2 2
= 0,73 for higher strength hull structural steel = − K tv ⋅ σ1 + 3 ⋅ τ1
with ReH = 390 N/mm2
for σ1 = compressive stress
If plate edges are free of notches and corners are rounded-
off, a 20 % higher notch stress σK may be permitted. Ktv = notch factor for equivalent stress
A further increase of stresses may be permitted on the = m⋅ ρ +c
basis of a fatigue strength analysis as per Section 20.
m, c = parameters according to Fig. 3.11

ℓ, a = length and height of opening

s1
6
a

τ1 = shear stress related to gross area of section

σ1 = longitudinal stress (in direction of length ℓ
5
of opening) related to gross area of section
s1
Kt r = radius of rounded corner
4
ρ = ratio of smaller length to radius of corner
(ℓ/r or a/r)
s1
3
a

ρmin = 3
s1
a

new F
2

s1 Note
a

1 Because the notch factor and the equivalent stress are

0,5 1
a/
1,5 2 2,5 always positive, the sign of σ1 governs the most unfa-
vourable superposition of the stress components in any
Fig. 3.9 Notch factor Kt for rounded openings of the four corners. A load consisting of shear only,
results in notch stresses of equal size with two positive
and two negative values in the opposite corners.

new F Note
I - Part 1 Section 3 J Design Principles Chapter 1
GL 2013 Page 3–19

s2
5.0 5.0

r
a
s1 s1

r
a
s1 s1

a/ = 2,5
a/ = 3 s1
4.0 a/ = 2 4.0 s2 =
Notch factor Kt

s2

Notch factor Kt
2

a/ = 1,5 a/ = 2

a/ = 1,5
3.0 a/ = 1 3.0

a/ =1
a/ = 1/2
a/ = 1/4
a/ = 1/4 a/ = 1/3
a/ = 1/2
2.0 2.0
0.0 0.1 0.2 0.3 0.4 0.5 0.0 0.1 0.2 0.3 0.4 0.5
Ratio r/a Ratio r/a

Fig. 3.10 Notch factor Kt for rectangular openings with rounded corners at uniaxial stress conditions (left)
and at biaxial stress conditions (right)

2.5 2.5
t1

2.0 2.0

r
a
s1 s1

1.5 1.5
m /a = 1/3 t1
c
/a = 1/2
1.0 1.0
/a = 2/3
/a = 1
0.5 /a = 3/2 0.5
/a = 2
/a = 3
0.0 0.0
0.0 0.2 0.4 0.6 0.8 1.0 2.0 3.0 4.0 5.0 ¥ 0.0 0.2 0.4 0.6 0.8 1.0 2.0 3.0 4.0 5.0 ¥
t1/s1 t1/s1

Fig. 3.11 Parameters m and c to determine the notch factors of rectangular openings loaded by superim-
posed longitudinal and shear stresses
Chapter 1 Section 3 K Design Principles I - Part 1
Page 3–20 GL 2013

An exact evaluation of notch stresses is possible by Table 3.6 Minimum corrosion additions
means of finite element calculations. For fatigue in-
vestigations the stress increase due to geometry of cut-
outs has to be considered, see Section 20, Table 20.3.
Area tKmin [mm]

In ballast tanks where the weather

new F
deck forms the tanktop, 1,5 m below 2,5
tanktop 1

Note – In cargo oil tanks where the

weather deck forms the tanktop,
1,5 m below tanktop. 2,0
These notch factors can only be used for girders with – Horizontal members in cargo oil
multiple openings if there is no correlation between and fuel oil tanks.
the different openings regarding deformations and
stresses. Deck plating below elastically
3,0
mounted deckhouses

new F Note Longitudinal bulkheads of ships

assigned to the Notation G and ex- 2,5
posed to grab operation
1
tK min = 2,5 mm for all structures within topside tanks of
K. Corrosion Additions bulk carriers.

1. The scantling requirements of the subsequent 3. For structures in dry spaces such as box gird-
Sections imply the following general corrosion addi- ers of container ships and for similar spaces the corro-
tions tK: sion addition is

0,1 t'
t K = 1,5 mm t' ≤ 10 mm tK = , max . 2,5 mm
k
0,1 ⋅ t'
= + 0,5 mm, max. 3,0 mm
k
however, not less than 1,0 mm.
t' > 10 mm

new G.3
t' = required rule thickness excluding tK [mm]
4. For inner walls and decks of dry spaces in-
k = material factor according to Section 2, B.2. side accommodation areas of ships, the corrosion
addition may be reduced to zero. In this case the decks
have to be protected by sheathing.

new G.1
For other superstructure areas the corrosion addition
has to be determined according to 1. with a minimum
2. For structural elements in specified areas tK thickness of tK = 1 mm.
is not to be less than given in Table 3.6:

new G.4

new G.2
5. Corrosion additions for hatch covers and
hatch coamings are to be determined according to
For corrosion protection see Section 35.
Section 17.

new G.6
new G.5

I - Part 1 Section 3 M Design Principles Chapter 1
GL 2013 Page 3–21

L. Additional Stresses in Asymmetric Sec- This additional stress σh is to be added directly to

tions/Profiles other stresses such as those resulting from local and
hull girder bending.
1. Additional stresses for fatigue strength
analysis
new B.3.7.1
The additional stress σh occurring in asymmetric sec-
tions may be calculated by the following formula :
2. Correction of section modulus
Q ⋅ ℓf ⋅ tf 2
σh = (b
1 − b 22 ) [N / mm 2 ]
c ⋅ Wy ⋅ Wz The required section modulus Wy according to A.2. is
to be multiplied with the factor ksp according to Table
Q = load on section parallel to its web within the 3.7.
unsupported span ℓf [kN]

new B.3.7.2
= p ⋅ a ⋅ ℓf [kN] in case of uniformly distrib-
uted load p [kN/m2]
Table 3.7 Increase factor ksp
ℓf = unsupported span of flange [m]
Type of Profile ksp
tf, b1, b2 = flange dimensions [mm], as shown in Fig.
3.12 Flat bars and symmetric T-profiles 1,00
Bulb profiles 1,03
z
b 
Asymmetric T − profiles  2 ≈ 0, 5  1,05
sh

 b1 
tf

Rolled angles (L-profiles) 1,15

hw

b1 b2
2
hw

M. Testing of Watertight and Weathertight

Compartments
z
y y
1. Tightness and structural testing of watertight
and weathertight compartments has to be done in
accordance with the IACS Unified Requirement S14.
Fig. 3.12 Asymmetric profiles
b1 ≥ b2
new H.1

c = factor depending on kind of load, stiffness of

the section's web and length and kind of sup- 2. For all tanks an operational test shall be car-
port of the profile. ried out when the ship is afloat or during the trial trip.
The proper functioning of filling and suction lines and
For profiles clamped at both ends and con- of the valves as well as functioning and tightness of
stant area load c = 80 can be taken for ap- the vent, sounding and overflow pipes is to be tested.
proximation. A precise calculation may be
required, e.g. for longitudinal frames of tank-
ers.
new H.2
Wy = section modulus of section related to the y-y
axis including the effective breadth of plating
3. Where in case of a tanker a pump room in-
[cm3] stead of a cofferdam is situated between cargo tank
Wz = section modulus of the partial section consist- and machinery space the engine room / pump room
bulkhead need not be water tested.
ing of flange and half of web area related to
the z-z axis [cm3], (bulb sections may be con-
verted into a similar L-section)
new H.3
I - Part 1 Section 4 A Design Loads Chapter 1
GL 2012 Page 4–1

Section 4

Design Loads

A. General, Definitions
for wave directions with or against the ship's
heading
1. General
p01 = 2,6 (CB + 0,7) ⋅ c0 ⋅ cL [kN/m2]
This Section provides data regarding design loads for
determining the scantlings of the hull structural ele- for wave directions transverse to the ship's
ments by means of the design formulae given in the heading
following Sections or by means of direct calculations. c0 = wave coefficient
The dynamic portions of the design loads are design
values which can only be applied within the design L 
concept of this Chapter. =  + 4,1 c RW for L < 90 m
 25 

new A.1
  300 − L  
1,5
= 10,75 −    cRW
2. Definitions   100  
2.1 Load centre for 90 ≤ L ≤ 300 m

2.1.1 For plates: = 10,75 ⋅ cRW for L > 300 m

– vertical stiffening system:
cL = length coefficient
0,5 × stiffener spacing above the lower support
of plate field, or lower edge of plate when the L
= for L < 90 m
thickness changes within the plate field 90
– horizontal stiffening system: = 1,0 for L ≥ 90 m
Midpoint of plate field
cRW = service range coefficient

new A.3
= 1,00 for unlimited service range
2.1.2 For stiffeners and girders:
= 0,90 for restricted service area RSA (200)
– centre of span ℓ
= 0,75 for restricted service area RSA (50)

new A.3
= 0,66 for restricted service area RSA (20)
2.2 Definition of symbols = 0,60 for restricted service area RSA (SW)
v0 = ship's speed according to Section 1, H.5.
f = probability factor
ρc = density of cargo as stowed [t/m3]
= 1,0 for plate panels of the outer hull (shell
ρ = density of liquids [t/m3] plating, weather decks)
= 1,0 t/m³ for fresh and sea water = 0,75 for secondary stiffening members and
z = vertical distance of the structure's load centre of the outer hull (frames, deck beams),
above base line [m] but not less than fQ according to
Section 5, D.1.
x = distance from aft end of length L [m]
= 0,60 for girders and girder systems of the
CB = moulded block coefficient according to outer hull (web frames, stringers, gril-
Section 1, H.4., where CB is not to be taken lage systems), but not less than
less than 0,6 fQ/1,25
p0 = basic external dynamic load
cD,cF = distribution factors according to Table 4.1
2
= 2,1 (CB + 0, 7) ⋅ c0 ⋅ cL ⋅ f [kN / m ]
new A.3
Chapter 1 Section 4 B Design Loads I - Part 1
Page 4–2 GL 2012

Table 4.1 Distribution factors for sea loads on ship's shell and weather decks

Range Factor cD Factor cF1

x x 5  x
A 0 ≤ < 0, 2 1, 2 − 1, 0 +  0, 2 − 
L L CB  L

x
M 0, 2 ≤ < 0, 7 1,0 1, 0
L
c x 
1, 0 +  − 0, 7 
3 L  2
x 20  x 
0, 7 ≤ ≤ 1, 0 1, 0 + − 0, 7 
F L c = 0,15 L – 10 CB  L 
100 m ≤ L ≤ 250 m

1 Within the range A the ratio x/L need not be taken less than 0,1, within the range F the ratio x/L need not be taken greater than 0,93.

Where the stowage height of deck cargo is less than

1,0 m, the deck cargo load may require to be increased
A M F by the following value:
x/L L pz = 10 (1 − h c ) [kN / m 2 ]
0 1,0
hc = stowage height of the cargo [m]
Fig. 4.1 Longitudinal sections A, M and F

new B.1
according to Table 4.1

2. Load on ship's sides and bow and stern

structures
B. External Sea Loads
2.1 Load on ship's sides
1. Load on weather decks The external load ps on the ship's sides is to be deter-
mined according to 2.1.1 and 2.1.2.
1.1 The load on weather decks is to be deter-
new B.2
mined according to the following formula:
20 ⋅ T 2.1.1 For elements the load centre of which is lo-
p D = p0 cD [kN / m 2 ] cated below load waterline:
(10 + z − T) H
 z

new B.1 ps = 10 ( T − z ) + p0 ⋅ c F 1 +  [kN / m 2 ]
 T
1.2 For strength decks which are to be treated as for wave directions with or against the ship's heading
weather decks as well as for forecastle decks the load
is not to be less than the greater of the following two  z  z  y
values: ps1 = 10 (T − z) + p01 1 +  2 −   ⋅ 2 [kN / m 2 ]
 T T  B
p D min = 16 ⋅ f [kN / m 2 ] for wave directions transverse to the ship's heading
and including quasi-static pressure increase due to heel
y = horizontal distance between load centre and
p D min = 0, 7 ⋅ p0 [kN / m 2 ] centreline [m]

new B.1
new B.2

2.1.2 For elements the load centre of which is lo-

1.3 Where deck cargo is intended to be carried on
the weather deck resulting in a load greater than the cated above load waterline:
value determined according to 1.1, the scantlings are
governed by the greater load (see also C.).
I - Part 1 Section 4 B Design Loads Chapter 1
GL 2012 Page 4–3

20 c = see 2.2
ps = p0 ⋅ c F [kN / m 2 ]
10 + z − T pe = shall not be smaller than ps according to 2.1.1
or 2.1.2 respectively
for wave directions with or against the ship's heading

new B.4
20 y 2
ps1 = p01 ⋅ [kN / m ]
5+ z−T B 3. Load on the ship's bottom
for wave directions transverse to the ship's heading The external load pB of the ship's bottom is to be de-
including quasi-static pressure increase due to heel termined according to the following formula:

new B.2
p B = 10 ⋅ T + p0 ⋅ c F [kN / m 2 ]
2.2 Load on bow structures

new B.5
The design load for bow structures from forward to
0,1 L behind F.P. and above the ballast waterline in
accordance with the draft Tb in 4. is to be determined 4. Design bottom slamming pressure
according to the following formula: The design bottom slamming pressure in the fore body
may be determined by the following formula:
2
pe (
= c 0, 20 ⋅ v0 + 0, 6 L ) [kN / m 2 ]
 1 + c RW 
pSL = 162 L ⋅ c1 ⋅ cSL ⋅ c A  
with L  2 
max = 300 m
for L ≤ 150 m

new B.3
 1 + cRW 
c = 0,8 in general = 1984 (1,3 − 0,002 L) c1 ⋅ cSL ⋅ cA  
 2 
0, 4 for L > 150 m
=
(1, 2 − 1, 09 ⋅ sin α ) 0,2
T 
for extremely flared sides where the flare c1 = 3,6 − 6,5  b  0 ≤ c1 ≤ 1,0
L
angle α is larger than 40°
The flare angle α at the load centre is to be measured Tb = smallest design ballast draught at F.P. for
in the plane of frame between a vertical line and the normal ballast conditions [m], according to
tangent to the side shell plating. which the strengthening of bottom forward,
see Section 6, E. has to be done.

new A.3
This value has to be recorded in the Annex to
For unusual bow shapes pe can be specially consid-
the Class Certificate and in the loading man-
ered. ual.
pe shall not be smaller than ps according to 2.1.1 or Where the sequential method for ballast wa-
2.1.2 respectively. ter exchange is intended to be applied, Tb is
Aft of 0,1 L from F.P. up to 0,15 L from F.P. the to be considered for the sequence of ex-
pressure between pe and ps is to be graded steadily. change.

The design load for bow doors is given in Section 6, H.3. Note

new B.3 With respect to the observation of the small-
est design ballast draught Tb, an exception is
2.3 Load on stern structures possible, if during the exchange of ballast
The design load for stern structures from the aft end to water weather conditions are observed the
0,1 L forward of the aft end of L and above the parameters of which are put down in the an-
smallest design ballast draught at the centre of the nex to the Certificate of Class.
rudder stock up to T + c0/2 is to be determined ac-
cording to the following formula:

pe = cA ⋅ L [kN / m 2 ]
with L max = 300 m

cA = 0, 3 ⋅ c ≥ 0, 36
Chapter 1 Section 4 C Design Loads I - Part 1
Page 4–4 GL 2012

cSL = 1,0 for the forecastle deck (covered by B.1)

1,0 nmin = 0,5

For deckhouses the value so determined may be mul-

0,5 tiplied by the factor

 b' 
 0,7 B' + 0,3 
0  
0,5 0,6 0,7 0,8 0,9 1,0 x/L
b' = breadth of deckhouse
Fig. 4.2 Distribution factor cSL
B' = largest breadth of ship at the position consid-
ered
cSL = distribution factor, see also Fig. 4.2
Except for the forecastle deck the minimum load is:
x
= 0 for ≤ 0,5
L p DA min = 4, 0 kN / m 2
x
− 0,5
new B.7.1
L x
= for 0,5 < ≤ 0,5 + c2
c2 L 5.2 For exposed wheel house tops the load is not
to be taken less than
x
= 1,0 for 0,5 + c2 < ≤ 0, 65 + c2
L p = 2,5 kN / m 2
 x 
new B.7.2
 1− 
L x
= 0,5 1 +  for > 0, 65 + c 2
 0,35 − c2  L
 
C. Cargo Loads, Load on Accommodation
L Decks
c2 = 0,33 ⋅ C B +
2500
1. Load on cargo decks
c2max = 0,35
cA = 10/A 1.1 The load on cargo decks is to be determined
according to the following formula:
= 1,0 for plate panels and stiffeners
pL = pc (1 + av) [kN/m2]
A = loaded area between the supports of the struc-
ture considered [m2] pc = static cargo load [kN/m2]
0,3 ≤ cA ≤ 1,0 If no cargo load is given: pc = 7 ⋅ h for 'tween decks
cRW = see A.2.2 but not less than 15 kN/m2.
h = mean 'tween deck height [m]

new B.6
In way of hatch casings the increased height of cargo
5. Load on decks of superstructures and is to be taken into account
deckhouses
new C.1.1

5.1 The load on exposed decks and parts of su- av = acceleration addition as follows:
perstructure and deckhouse decks, which are not to be av = F ⋅ m
treated as strength deck, is to be determined as fol-
lows: v0
F = 0,11
p DA = pD ⋅ n [kN / m ] 2 L
x x
pD = load according to 1.1 m = mo − 5 (mo − 1) for 0 ≤ ≤ 0, 2
L L
z − H x
n = 1 − = 1,0 for 0, 2 < ≤ 0,7
10 L
I - Part 1 Section 4 D Design Loads Chapter 1
GL 2012 Page 4–5

m0 + 1  x  x av = see 1.1
= 1+ − 0,7  for 0, 7 < ≤ 1, 0
0,3  L  L For calculating av the distance between the
centre of gravity of the hold and the aft end
m0 = (1,5 + F) of the length L is to be taken.
v0 = see A.2.2. v0 is not to be taken less than
new C.2.1
L [kn]

new A.3 2.2 For inner bottom load in case of ore stowed
in conical shape, see Section 23, B.3.
1.2 For timber and coke deck cargo the load on
new C.2.1
deck is to be determined by the following formula:
3. Loads on accommodation and machinery
p L = 5 ⋅ h s (1 + a v ) [kN / m 2 ] decks
hs = stowing height of cargo [m] 3.1 The deck load in accommodation and service

new C.1.2 spaces is:

p = 3,5 (1 + a v ) [kN / m 2 ]
1.3 The loads due to single forces PE (e.g. in case
of containers) are to be determined as follows:
new C.3
P = PE (1 + a v ) [kN] 3.2 The deck load of machinery decks is:

new C.1.3 p = 8 (1 + a v ) [kN / m 2 ]

1.4 The cargo pressure of bulk cargoes is to be
new C.3

determined by the following formula:
3.3 Significant single forces are also to be con-
pbc = pc (1 + av) [kN/m2] sidered, if necessary.

pc = static bulk cargo load
new C.3

= 9,81⋅ ρc ⋅ h ⋅ n [kN/m2]
h = distance between upper edge of cargo and the
D. Loads on Tank Structures
load centre [m]

 γ 1. Design pressure for filled tanks

n = tan 2  45° −  sin 2 α + cos 2 α
 2
1.1 The design pressure for service conditions is
α = angle in degrees between the structural ele- the greater of the following values:
ment considered and a horizontal plane
p1 = 9,81 ⋅ h1 ⋅ ρ (1 + av) + 100 ⋅ pv [kN/m2]
γ = angle of repose of the cargo in degrees
or

new C.1.4
p1 = 9,81⋅ ρ[h1⋅ cosϕ + (0,3 ⋅ b + y) sinϕ] + 100 ⋅ pv [kN/m2]
2. Load on inner bottom h1 = distance from load centre to tank top [m]
2.1 The inner bottom cargo load is to be deter- av = see C.1.1
mined as follows:
ϕ = design heeling angle [°] for tanks
G
pi = 9,81 ⋅ ⋅ h (1 + a v ) [kN / m 2 ]  H
V = arctan  f bk ⋅  in general
 B
G = mass of cargo in the hold [t] fbk = 0,5 for ships with bilge keel
V = volume of the hold [m³] (hatchways ex-
= 0,6 for ships without bilge keel
cluded)
h = height of the highest point of the cargo above ϕ ≥ 20° for hatch covers of holds carrying
the inner bottom [m], assuming hold to be liquids
completely filled b = upper breadth of tank [m]
Chapter 1 Section 4 D Design Loads I - Part 1
Page 4–6 GL 2012

y = distance of load centre from the vertical h2.4 = distance [m] from load centre to a point 10 ⋅
longitudinal central plane of tank [m] pv [m] above tank top, if a pressure relief valve

new D.1.1 is fitted. Set pressure pv of pressure relief valve
is not to be taken less than 0,25 ⋅ ρ [bar].
For cargo tanks of tankers equipped with a pressure
relief valve,
new D.1.2

pv = set pressure [bar] of pressure relief valve, 2. Design pressure for partially filled tanks
not to be taken less than 0,2 bar (see also
the GL Rules for Machinery Installations 2.1 For tanks which may be partially filled be-
(I-1-2), Section 15). Smaller set pressures tween 20 % and 90 % of their height, the design pres-
than 0,2 bar may be accepted in special sure is not to be taken less than given by the following
cases. The actual set pressure will be en- formulae:
tered into the class certificate.

new D.2.1
For ballast water tanks,
2.1.1 For structures located within ℓt/4 from the
pv = working pressure [bar] during ballast water
bulkheads limiting the free liquid surface in the ship's
exchange, not to be taken less than 0,1 bar
longitudinal direction:
for the sequential method as well as for the
flow-through method.
 L 
pd =  4 − ℓ t ⋅ ρ ⋅ n x + 100 ⋅ p v [kN / m 2 ]
∆z − 2,5  150 
= + ∆p v
10
ℓt = distance [m] between transverse bulkheads or
If the ballast water exchange is done by
using a ring-ballast system and the dilution effective transverse wash bulkheads at the
method, for which an equivalent inflow height where the structure is located.
and outflow is to be ensured, pv = 0 bar can
new D.2.1.1
be used.
2.1.2 For structures located within bt/4 from the
∆z = distance [m] from tank top to top of over-
bulkheads limiting the free liquid surface in the ship's
flow used for ballast water exchange.
transverse direction:
∆pv = pressure losses [bar] in the overflow line
during ballast water exchange, not to be  B
pd =  5,5 − b t ⋅ ρ ⋅ n y + 100 ⋅ p v [kN / m 2 ]
taken less than 0,1 bar (see also the GL  20 
Guidelines for the Construction, Equipment
and Testing of Closed Fuel Oil Overflow bt = distance [m] between tank sides or effective
Systems (VI-3-6), Annex A, 3.1 longitudinal wash bulkhead at the height

new A.3 where the structure is located

new D.2.1.2
1.2 The maximum static design pressure is:
4
p 2 = 9,81 ⋅ h 2 [kN / m 2 ] nx = 1 − x1
ℓt

h2 = max (h2,1, h2,2, h2,3, h2,4)
new D.2.1.1

h2.1 = distance [m] from load centre to top of over- 4

ny = 1 − y1
flow according to Section 21, E. Tank vent- bt
ing pipes of cargo tanks of tankers are not to
be regarded as overflow pipes.
new D.2.1.2

h2.2 = distance [m] from load centre to a point 2,5 ⋅ ρ x1 = distance of structural element from the tank's
[m] above tank top. Density of liquid intended ends in the ship's longitudinal direction [m]
to be carried is not to be taken less than 1 t/m3.
new D.2.1.1
h2.3 = distance [m] from load centre to the highest y1 = distance of structural element from the tank's
point of overflow system, if the tank is con- sides in the ship's transverse direction [m]
nected to such a system. The dynamic pres-
sure increase due to overflowing is to be
new D.2.1.2
taken into account in addition to the static
pressure p2 (see also the GL Guidelines for 2.2 For tanks with ratios ℓt/L > 0,1 or bt/B > 0,6
the Construction, Equipment and Testing of a direct calculation of the pressure pd may be re-
Closed Fuel Oil Overflow Systems (VI-3-6). quired.
I - Part 1 Section 4 E Design Loads Chapter 1
GL 2012 Page 4–7

new D.2.2 GM = metacentric height [m]

kmin = 1,0
E. Design Values of Acceleration Components fQ = probability factor depending on probability
level Q as outlined in Table 4.2
1. Acceleration components
The following formulae may be taken for guidance
new E.1
when calculating the acceleration components owing
to ship's motions.
Table 4.2 Probability factor fQ for a straight-
Vertical acceleration:
line spectrum of seaway-induced
1,5
stress ranges
2 2
 45   x   0,6 
az = ± a0 1 +  5,3 −
L   L
− 0,45   
   CB 
Q fQ
Transverse acceleration: 10–8 1,000
2 2
10–7 0,875
x   z − T 10–6 0,750
ay = ± a0 0,6 + 2,5  − 0,45 + k 1 + 0,6 ⋅ k
L   B  10–5 0,625
10–4 0,500
Longitudinal acceleration:

ax = ± a0 0, 06 + A 2 − 0, 25 A
2. Combined acceleration
where
 L z − T  0, 6
A =  0, 7 − + 5
L  CB
The combined acceleration aß may be determined by
 1200
means of the "acceleration ellipse" according to
Fig. 4.3 (e.g. y-z-plane).
The acceleration components take account of the fol-
lowing components of motion:

new E.2
Vertical acceleration (vertical to the base line) due to
heave and pitch.
Transverse acceleration (vertical to the ship's side) centre of gravity
due to sway, yaw and roll including gravity compo-
nent of roll.
Longitudinal acceleration (in longitudinal direction) b
due to surge and pitch including gravity component of
pitch. b max
1,0

ax, ay and az are maximum dimensionless accelera-

tions (i.e., relative to the acceleration of gravity g) in
the related directions x, y and z. For calculation pur-
ab

poses they are considered to act separately. ay

 v 3 ⋅ c0 ⋅ c L 
a 0 =  0, 2 0 +  fQ
az

 L0 L0 
 

L0 = length of ship L [m], but for determination of at L/2

a0 the length L0 shall not be taken less than
100 m

13 ⋅ GM at the ends
k = C.L.
B
Fig. 4.3 Acceleration ellipse
I - Part 1 Section 5 A Longitudinal Strength Chapter 1
GL 2012 Page 5–1

Section 5

Longitudinal Strength

A. General

new E.1.2.2.2
1. Scope 3.3 For other ship types and special ships, the
calculation of bending moments and shear forces for
1.1 For ships of categories I – II as defined in other loading conditions according to the intended
4.1.3, the scantlings of the longitudinal hull structure service may be required to be investigated, see also G.
are to be determined on the basis of longitudinal bend-
ing moments and shear forces calculations. For ships
new B.3.1
which do not belong to these categories i.e. in general
for ships of less than 65 m in length, see Section 7, A.4. 3.4 Where for ships of unusual design and form
as well as for ships with large deck openings a com-

new A.1.1 plex stress analysis of the ship in the seaway becomes
necessary, the analysis will normally be done at the
1.2 The wave bending moments and shear forces Head Office by using computer programs of GL and
specified under B.3. are design values which, in con- processing the data prepared by the yard.
nection with the scantling formulae, correspond to a
probability level of Q = 10–8. Reduced values may be
used for the purpose of determining combined stresses 4. Loading guidance information
as specified under D.1.
4.1 General, definitions

new A.1.3
4.1.1 Loading guidance information 1 is a means in
2. Calculation particulars accordance with Regulation 10(1) of ICLL which
The curves of the still water bending moments and enables the master to load and ballast the ship in a safe
still water shear forces for the envisaged loading and manner without exceeding the permissible stresses.
ballast conditions are to be calculated.
new C.1

new D.1.1.2
4.1.2 An approved loading manual is to be supplied
for all ships except those of Category II with length
3. Assumptions for calculation, loading con- less than 90 m in which the deadweight does not ex-
ditions ceed 30 % of the displacement at the summer loadline.
3.1 The calculation of still water bending mo-
new C.3.1
ments and shear forces is to be carried out for the
In addition, an approved loading instrument is to be
following three loading conditions:
supplied for all ships of Category I of 100 m in length
– departure condition and above. In special cases, e. g. extreme loading con-
– arrival condition ditions or unusual structural configurations, GL may
also require an approved loading instrument for ships
– transitory conditions (reduced provisions and of Category I less than 100 m in length.
ballast variations between departure and arrival)

new C.4.1
For determining the scantlings of the longitudinal hull
structure, the maximum values of the still water bend- Special requirements for bulk carriers, ore carriers and
ing moments and shear forces are to be used. combination carriers are given in Section 23, B.10.

new B.1.1
new A.2.2

3.2 In general, the loading conditions specified in 4.1.3 The following definitions apply:
4.3.2 are to be investigated. Loading manual is a document which describes:

new B.1.1 – the loading conditions on which the design of the
To enable increased operating flexibility of the ship, ship has been based, including permissible limits
loading conditions with high masses at cargo hold
ends or ship's ends respectively should be considered
during the design phase. 1 Upon request, GL will prepare the loading guidance informa-
tion.
Chapter 1 Section 5 A Longitudinal Strength I - Part 1
Page 5–2 GL 2012

of still water bending moment and shear force Chemical tankers and gas carriers.
and shear force correction values and, where ap-
Ships more than 120 metres in length, where the cargo
plicable, permissible limits related to still water
and/or ballast may be unevenly distributed.
torsional moment and lateral loads
Ships less than 120 metres in length, when their de-
– the results of calculations of still water bending
sign takes into account uneven distribution of cargo or
moments, shear forces and still water torsional
ballast, belong to Category II.
moments if unsymmetrical loading conditions
with respect to the ships centreline Category II Ships:
– the allowable local loadings for the structure Ships with arrangement giving small possibilities for
(hatch covers, decks, double bottom, etc.) variation in the distribution of cargo and ballast (e.g.

new C.3.2 passenger vessels).

A loading instrument 2 is an approved analogue or Ships on regular and fixed trading patterns where the
digital instrument consisting of loading manual gives sufficient guidance.

– loading computer (Hardware) and The exception given under Category I.

– loading program (Software)
new C.2

by means of which it can be easily and quickly ascer- 4.2 Conditions of approval for loading manual
tained that, at specified read-out points, the still water
bending moments, shear forces, and the still water The approved loading manual is to be based on the
torsional moments and lateral loads, where applicable, final data of the ship. The manual shall include the
in any load or ballast condition will not exceed the design loading and ballast conditions upon which the
specified permissible values. approval of the hull constructional units is based.

An approved operational manual is always to be pro- 4.3.2 contains, as guidance only, a list of the loading
vided for the loading instrument. The operational conditions which, in general, are to be included in the
manual is to be approved. loading manual. In case of modifications resulting in
changes in the main data of the ship, a newly approved

new C.4.2 loading manual is to be issued.
Loading computers have to be type tested and certi- The loading manual shall be prepared in a language
fied, see also 4.5.1. Type approved hardware may be understood by the users. If this language is not Eng-
waived, if redundancy is ensured by a second certified lish, a translation into English is to be included.
loading instrument. Type approval is required if

new C.3.4
– the computers are installed on the bridge or in
adjacent spaces 4.3 Design cargo and ballast loading conditions
– interfaces to other systems of ship operation are
provided 4.3.1 In general the loading manual should contain
the design loading and ballast conditions, subdivided
For type approval the relevant rules and guidelines are into departure and arrival conditions and, where appli-
to be observed. cable, ballast exchange at sea conditions upon which
the approval of the hull scantlings is based.
Loading programs shall be approved and certified, see
also 4.4.1 and 4.5.2. Single point loading programs are
new C.3.3
not acceptable.
Where the amount and disposition of consumables at

Guidelines for Loading Computer Systems VI-11-7 any transitory stage of the voyage are considered to
result in a more severe loading condition, calculations
Ship categories for the purpose of this Section are
defined for all classed seagoing ships of 65 m in for such transitory conditions are to be submitted in
length and above which were contracted for construc- addition to those for departure and arrival conditions.
tion on or after 1st July 1998 as follows: Also, where any ballasting and/or deballasting is in-
tended during voyage, calculations of the transitory
Category I Ships: conditions before and after ballasting and/or deballast-
Ships with large deck openings where, according to F., ing any ballast tank are to be submitted and, after
combined stresses due to vertical and horizontal hull approval, included in the loading manual for guidance.
girder bending and torsional and lateral loads have to
new B.1.1
be considered.
4.3.1.1 Partially filled ballast tanks in ballast load-
ing conditions
2 For definition of the whole loading computer system, which
may consist of further modules e.g. stability computer accord- Ballast loading conditions involving partially filled
ing to IACS UR L5, see the GL Guidelines for Loading Com- peak and/or other ballast tanks at departure, arrival or
puter Systems (VI-11-7).
I - Part 1 Section 5 A Longitudinal Strength Chapter 1
GL 2012 Page 5–3

during intermediate conditions are not permitted to be tions for each (reasonable, scantling determining)
considered as design conditions, unless deballasting or ballasting stage in the ballast water
exchange sequence are to be included in the loading
– design stress limits are not exceeded in all filling
manual or ballast water management plan of any ves-
levels between empty and full;
sel that intends to employ the sequential ballast water
– for bulk carriers, where applicable, the require- exchange method.
ments of G. are complied with for all filling lev-

new B.4.3
els between empty and full.
To demonstrate compliance with all filling levels 4.3.2 In particular the following loading conditions
between empty and full, it will be acceptable if, in are to be checked:
each condition at departure, arrival and where required For Dry-Cargo Ships, Containerships, Ro-Ro Ships,
by 4.3.2 any intermediate condition, the tanks in- Refrigerated Carriers, Ore Carriers and Bulk Carriers:
tended to be partially filled are assumed to be:
– loading conditions at maximum draught
– empty
– ballast conditions
– full
– special loading conditions, e.g.
– partially filled at intended level
– container or light load conditions at less than
Where multiple tanks are intended to be partially filled, the maximum draught
all combinations of empty, full or partially filled at
intended level for those tanks are to be investigated. – heavy cargo, empty holds or non-homogene-
ous cargo conditions
However, for conventional ore carriers with large
wing water ballast tanks in cargo area, where empty or – deck cargo conditions, etc., where applicable
full ballast water filling levels of one or maximum two – short voyages or harbour conditions, where
pairs of these tanks lead to the ship's trim exceeding applicable
one of the following conditions, it is sufficient to dem-
onstrate compliance with maximum, minimum and – docking conditions afloat
intended partial filling levels of these one or maxi- – loading and unloading transitory conditions,
mum two pairs of ballast tanks such that the ship's where applicable
condition does not exceed any of these trim limits.
Filling levels of all other wing ballast tanks are to be – all loading conditions specified in Section 23,
considered between empty and full. F.4. for ships with Notations BC-A, BC-B or
BC-C, where applicable
The trim conditions mentioned above are:
– trim by stern of 0,03 L, or For oil tankers (see also Section 24, B.):

– trim by bow of 0,015 L, or – homogeneous loading conditions (excluding dry

and segregated ballast tanks) and ballast or part-
– any trim that cannot maintain propeller immer- loaded conditions for both departure and arrival
sion (I/D) not less than 25%
– any specified non-uniform distribution of loading
I = the distance from propeller centreline to the – mid-voyage conditions relating to tank cleaning
waterline or other operations where these differ signifi-
D = propeller diameter cantly from the ballast conditions

The maximum and minimum filling levels of the – docking conditions afloat
above mentioned pairs of side ballast tanks are to be – loading and unloading transitory conditions
indicated in the loading manual.
For chemical tankers:

new B.4.1
– conditions as specified for oil tankers
4.3.1.2 Partially filled ballast tanks in combina- – conditions for high density or heated cargo, see
tion with cargo loading conditions also Section 12, A.6.
In such cargo loading conditions, the requirements in – segregated cargo where these are included in the
4.3.1.1 apply to the peak tanks only. approved cargo list

new B.4.2 For liquefied gas carriers:
4.3.1.3 Sequential ballast water exchange – homogeneous loading conditions for all ap-
proved cargoes for both arrival and departure
Requirements of 4.3.1.1 and 4.3.1.2 are not applicable
to ballast water exchange using the sequential method. – ballast conditions for both arrival and departure
However, bending moment and shear force calcula-
Chapter 1 Section 5 A Longitudinal Strength I - Part 1
Page 5–4 GL 2012

– cargo condition where one or more tanks are The permissible limits for the still water bending mo-
empty or partially filled or where more than one ments and shear forces to be applied for the ballast
type of cargo having significantly different den- water exchange at sea are to be determined in accor-
sities is carried for both arrival and departure dance with E., where B.3.1 is to be used for the wave
bending moments and B.3.2 for the wave shear forces.
– harbour conditions for which an increased vapour
pressure has been approved (see the GL Rules for
Guidelines for Loading Computer Systems VI-11-7
Liquefied Gas Tankers (I-1-6), Section 4, 4.2.6.4)
For ballast water exchange see also the GL Guidelines
– docking conditions afloat on Ballast Water Management (VI-11-10).
For combination carriers:
new B.4
– conditions as specified for oil tankers and cargo
ships 4.5 Approval procedures for loading instru-
ments

new B.2
4.5.1 Type test of the loading computer
4.4 Conditions of approval for loading instru- The type test requires:
ments
– The loading computer has to undergo successful
4.4.1 The approval of the loading instrument is to tests in simulated conditions to prove its suit-
include: ability for shipboard operation.
– verification of type approval, if required, see 4.1.3 – The qualification test can be dropped if a load-
– verification that the final data of the ship have ing instrument has been tested and certified by
been used an independent and recognized authority, pro-
vided the testing program and results are con-
– acceptance of number and position of read-out sidered satisfactory.
points

Guidelines for Loading Computer Systems VI-11-7
– acceptance of relevant limits for all read-out
points 4.5.2 Certification of the loading program
– checking of proper installation and operation of 4.5.2.1 After the successful type test of the hardware,
the instrument on board in accordance with if required, see 4.1.3, the producer of the loading pro-
agreed test conditions and availabilty of an ap- gram shall apply at GL for certification.
proved operation manual

Guidelines for Loading Computer Systems VI-11-7

Guidelines for Loading Computer Systems VI-11-7
4.5.2.2 The number and location of read-out points
4.4.2 4.5 contains information on approval proce- are to be to the satisfaction of GL. Read-out points
dures for loading instruments. should usually be selected at the position of the trans-

Guidelines for Loading Computer Systems VI-11-7 verse bulkheads or other obvious boundaries. Addi-
tional read-out points may be required between bulk-
4.4.3 In case of modifications implying changes in heads of long holds or tanks or between container
the main data of the ship, the loading program is to be stacks.
modified accordingly and newly approved.
Guidelines for Loading Computer Systems VI-11-7

Guidelines for Loading Computer Systems VI-11-7
4.5.2.3 GL will specify:
4.4.4 The operation manual and the instrument – the maximum permissible still water shear
output shall be prepared in a language understood by forces, bending moments (limits) at the agreed
the users. If this language is not English, a translation read-out points and when applicable, the shear
into English is to be included. force correction factors at the transverse bulk-

Guidelines for Loading Computer Systems VI-11-7 heads
– when applicable, the maximum permissible tor-
4.4.5 The operation of the loading instrument is to sional moments
be verified upon installation. It is to be checked that
the agreed test conditions and the operation manual – when applicable, the maximum lateral load
for the instrument are available on board.

Guidelines for Loading Computer Systems VI-11-7
4.5.2.4 For approval of the loading program the
following documents have to be handed in:
– operation manual for the loading program
I - Part 1 Section 5 A Longitudinal Strength Chapter 1
GL 2012 Page 5–5

– print-outs of the basic ship data like distribution eD = distance [m] between neutral axis of hull
of light ship weight, tank and hold data etc. section and deck line at side
– print-outs of at least 4 test cases Iy = moment of inertia of the midship section [m4]
– diskettes with loading program and stored test around the horizontal axis at the position x/L
cases ez = vertical distance of the structural element
The calculated strength results at the fixed read-out considered from the horizontal neutral axis
points shall not differ from the results of the test cases [m] (positive sign for above the neutral axis,
by more than 5 % related to the approved limits. negative sign for below)

Guidelines for Loading Computer Systems VI-11-7 k = material factor according to Section 2, B.2.

4.5.3 Loading instrument MSW = permissible vertical still water bending mo-
ment [kNm] (positive sign for hogging, nega-
Final approval of the loading instrument will be tive sign for sagging condition)
granted when the accuracy of the loading instrument
has been checked after installation on board ship using MWV = vertical wave bending moment [kNm] (posi-
the approved test conditions. tive sign for hogging, MWVhog, negative sign
for sagging condition, MWVsag)
If the performance of the loading instrument is found
satisfactory during the installation test on board, the MT = total bending moment in the seaway [kNm]
certificate issued by GL Head Office and handed over = MSW + MWV
on board will become valid. The Installation Test
Report should be stamped and signed by the Master. MWH = horizontal wave bending moment [kNm]
(positive sign for tension in starboard side,
During the next six months after the issue of certifi-
negative for compression in starboard side)
cate, the Installation Test Report has to be checked by
GL surveyor. He has to stamp and sign it, if all docu- MST = static torsional moment [kNm]
ments are available on board, the Installation Onboard
Test has been carried out satisfactorily and the system MWT = wave induced torsional moment [kNm]
is running without any problem.
QSW = permissible vertical still water shear force

Guidelines for Loading Computer Systems VI-11-7 [kN]
QWV = vertical wave shear force [kN]
4.6 Class maintenance of loading guidance
information QT = total vertical shear force in the seaway [kN]
At each Annual and Class Renewal Survey, it is to be = QSW + QWV
checked that the approved loading guidance informa-
tion is available on board. QWH = horizontal wave shear force [kN]
The loading instrument is to be checked for accuracy v0 = speed of the ship [kn] according to Section 1,
at regular intervals by the ship's Master by applying H.5.
test loading conditions. At each Class Renewal Survey x = distance [m] between aft end of length L and
this checking is to be checked in the presence of the the position considered
Surveyor.
Sign rule see Fig. 5.1

new C.5

new A.3
5. Definitions
z
CB = block coefficient as defined in Section 1, H.4.
x
CB is not to be taken less than 0,6 (+)
c0 = wave coefficient according to Section 4,
y
A.2.2
cL = length coefficient according to Section 4, L
A.2.2
eB = distance [m] between neutral axis of hull
section and base line Fig. 5.1 Sign rule
Chapter 1 Section 5 B Longitudinal Strength I - Part 1
Page 5–6 GL 2012

B. Loads on the Ship's Hull
new D.1.2.1.1

1. General 2.2.2 Static torsional moment

In general the global loads on the hull in a seaway can The maximum static torsional moment may be deter-
be calculated with the formulas stated below. mined by:

For ships of unusual form and design (e.g. L/B ≤ 5, MST max = ± 20 ⋅ B ⋅ CC [kNm]
B/H ≥ 2,5, L ≥ 500 m or CB < 0,6) and for ships with
a speed of: CC = maximum permissible cargo capacity of the
ship [t]
v0 ≥ 1,6 ⋅ L [kn]
= n⋅G
as well as for ships with large bow and stern flare and n = maximum number of 20'-containers (TEU) of
with cargo on deck in these areas GL may require the mass G the ship can carry
determination of wave bending moments as well as
their distribution over the ship's length by approved G = mean mass of a single 20'-container [t]
calculation procedures. Such calculation procedures For the purpose of a direct calculation the following
shall take into account the ship's motions in a natural envelope curve of the static torsional moment over the
seaway. ship's length is to be taken:

new A.1.2
MST = 0,568 ⋅ MST max ( cT1 + cT2 ) [kNm]
2. Still water loads
cT1, cT2 = distribution factors, see also Fig. 5.2
2.1 General
cT1
Due to the provided loading cases the vertical longitu-
dinal bending moments and shear forces are to be
+1
proved by calculations for cases in intact conditions
(MSW, QSW) and if required (see G.1.) for damage
conditions (MSWf, QSWf).
0 x/L
If statical torsional moments are likely to be expected 0,5 1,0
from the loading or construction of the ship, they have
to be taken into account.
-1

new D.1.1.1
Still water loads have to be superimposed with the
wave induced loads according to 3. cT2

new D.1.1.3 +1

2.2 Guidance values for container ships with

irregular loading
x/L
2.2.1 Still water bending moments 0 0,5 1,0

When determining the required section modulus of the Fig. 5.2 Distribution factors cT1 and cT2 for
midship section of container ships in the range: torsional moments
x x  x x
= 0,3 to = 0,55 cT1 = sin 0,5  2 π  for 0≤ < 0, 25
L L  L L
it is recommended to use at least the following initial
value for the hogging still water bending moment:  x x
= sin  2 π  for 0, 25 ≤ ≤ 1, 0
 L L
MSWini = n1 ⋅ c0 ⋅ L2 ⋅ B ⋅ ( 0,123 − 0, 015 ⋅ CB ) [kNm]
 x x
cT2 = sin  π  for 0≤ < 0,5
  n  
2  L L
n1 = 1, 07 ⋅ 1 + 15 ⋅   ≤ 1, 2
 5  
  10    x x
= sin 2  π  for 0,5 ≤ ≤ 1, 0
 L L
n = according to 2.2.2
MSWini shall be graduated regularly to ship's ends.
new D.1.2.1.2
I - Part 1 Section 5 B Longitudinal Strength Chapter 1
GL 2012 Page 5–7

3. Wave induced loads
new D.1.3.1

3.1 Vertical wave bending moments 3.2 Vertical wave shear forces
The vertical wave bending moments are to be deter- The vertical wave shear forces are to be determined by
mined according to the following formula: the following formula:

M WV = L2 ⋅ B ⋅ c0 ⋅ c1 ⋅ cL ⋅ c M [kNm] Q WV = c0 ⋅ cL ⋅ L ⋅ B ⋅ ( CB + 0, 7 ) ⋅ cQ [kN]

c0,cL = see Section 4, A.2.2 c0, cL = see Section 4, A.2.2

c1 = hogging, sagging condition, as follows: cQ = distribution factor according to Table 5.1, see
also Fig. 5.4
c1H = 0,19 ⋅ CB for hogging condition
c1H
c1S = – 0,11 (CB + 0,7) for sagging condition m = −
c1S
cM = distribution factor, see also Fig. 5.3
c1H, c1S = see 3.1
cMH = hogging condition

new D.1.3.2
x x
= 2,5 ⋅ for 0 ≤ < 0, 4
L L M
= 1,0 for 0, 4 ≤
x
≤ 0, 65 Hogging
L M U,H
x
1, 0 −
L x
= for 0, 65 < ≤1
0,35 L

cM
c
cv
1,0

cMS Sagging
cMH M U,S

x/L
0,65 × cv Fig. 5.4 Distribution factor cQ
0 0,4 0,65 1,0

3.3 Horizontal bending moments

Fig. 5.3 Distribution factor cM and influence
factor cv
M WH = 0,32 ⋅ L ⋅ Q WH max ⋅ cM [kNm]
cMS = sagging condition
x x cM = see 3.1, but for cv = 1
= c v ⋅ 2,5 for 0 ≤ < 0, 4
L L
QWHmax = see 3.4
x
= cv for 0,4 ≤ ≤ 0,65 ⋅ cv
L
new D.1.3.3
x
− 0, 65 ⋅ c v
x
= cv − L for 0, 65 ⋅ c v < ≤ 1 3.4 Horizontal shear forces
1 − 0, 65 ⋅ c v L
cv = influence factor with regard to speed v0 of the QWHmax = ± cN ⋅ L ⋅ T ⋅ B ⋅ CB ⋅ c0 ⋅ cL [kN]
vessel
L
v0 cN = 1 + 0,15
= 3 ≥ 1, 0 B
1, 4 ⋅ L
cNmin = 2
for L the value need not be less than 100
= 1,0 for damaged condition QWH = QWHmax ⋅ cQH
Chapter 1 Section 5 B Longitudinal Strength I - Part 1
Page 5–8 GL 2012

cQH = distribution factor acc. to Table 5.2, see cQH

also Fig. 5.5
1

new D.1.3.4
0,5

0,15
0 0,1 0,3 0,4 0,6 0,7 0,8 1

Fig. 5.5 Distribution factor cQH

Table 5.1 Distribution factor cQ

Range for positive shear forces for negative shear forces

x x x
0 ≤ < 0, 2 1,38 ⋅ m ⋅ − 1,38 ⋅
L L L
x
0,2 ≤ < 0,3 0,276 ⋅ m – 0,276
L
x x  x
0,3 ≤ < 0, 4 1,104 ⋅ m − 0,63 + ( 2,1 − 2,76 ⋅ m ) ⋅ −  0,474 − 0,66 ⋅ 
L L  L

x
0,4 ≤ < 0, 6 0,21 – 0,21
L
x x   x
0,6 ≤ < 0, 7 (3 ⋅ cv − 2,1) ⋅  − 0, 6  + 0,21 −  1,47 − 1,8 ⋅ m + 3 ⋅ ( m − 0,7 ) ⋅ 
L L   L

x − 0,3 ⋅ m
0,7 ≤ < 0,85 0,3 ⋅ c v
L
x 1   x  x   x
0,85 ≤ ≤ 1,0 ⋅  c v ⋅  14 ⋅ − 11  − 20 ⋅ + 17  − 2 ⋅ m ⋅ 1 − 
L 3   L  L   L
I - Part 1 Section 5 C Longitudinal Strength Chapter 1
GL 2012 Page 5–9

Table 5.2 Distribution factor cQH The envelope can be approximated by superposition of
both distributions according to Fig. 5.2.
Range cQH
new D.1.3.5 Note
x x
0 ≤ < 0,1 0, 4 + 6 ⋅
L L CWT
x
0,1 ≤ ≤ 0,3 1
L a = 0,5

0,3 <
x
< 0, 4 x  0,5
1, 0 − 5 ⋅  − 0,3  a = 0,35
L L 
0,4
x
0, 4 ≤ ≤ 0, 6 0,5 0,3
L a = 0,1
x x  0,2
0, 6 < < 0, 7 0,5 + 5 ⋅  − 0, 6 
L L  0,1 x
L
x
0, 7 ≤ ≤ 0,8 1,0 0,0 0,5 1,0
L

0,8 <
x
≤ 1, 0 x 
1, 0 − 4, 25 ⋅  − 0,8  Fig. 5.6 Distribution factor cWT
L  L 

3.5 Torsional moments C. Section Moduli, Moments of Inertia, Shear

The maximum wave induced torsional moment is to and Buckling Strength
be determined as follows:
1. Section moduli as a function of the longi-
M WT max = ± L ⋅ B2 ⋅ CB ⋅ c0 ⋅ cL tudinal bending moments

⋅ 0,11 + a 2 + 0,012  [kNm]

1.1 The section moduli related to deck WD re-
  spectively WD' or bottom WB are not to be less than:

T c N ⋅ zQ MSW + M WV
a = ⋅ W = fr ⋅ [m3 ]
L B σp ⋅ 103
amin = 0,1 fr = 1,0 in general
cN = see 3.4 = according to F.2. for ships with large openings
zQ = distance [m] between shear centre and a σp = permissible longitudinal bending stress
level at [N/mm2]
B⋅ H = cs ⋅ σp0
0, 2
T
above the basis 18,5 ⋅ L
σp0 = for L < 90 m
k
When a direct calculation is performed, for the wave
induced torsional moments the following envelope 175
= for L ≥ 90 m
curve is to be taken: k

M WT = ± L ⋅ B 2 ⋅ CB ⋅ c0 ⋅ cL ⋅ c WT [kNm] 5 x x
cs = 0,5 + ⋅ for 0 ≤ < 0,3
3 L L
cWT = distribution factor, see also Fig. 5.6
x
= 1,0 for 0,3 ≤ ≤ 0, 7
= a ⋅ cT1 + 0, 22 ⋅ cT2  ⋅ ( 0,9 + 0, 08 ⋅ a ) L

cT1, cT2 = see 2.2.2 5  x x

= ⋅ 1,3 −  for 0, 7 < ≤ 1, 0
3  L L

new D.1.3.5

new E.1.2.1.1
Note
Chapter 1 Section 5 C Longitudinal Strength I - Part 1
Page 5–10 GL 2012

1.2 For the ranges outside 0,4 L amidships the scantlings may be gradually reduced towards the end
factor may be increased up to cs = 1,0 if this is justi- of the 0.4 L part, bearing in mind the desire not in-
fied under consideration of combined stresses due to habit the vessel's loading flexibility, see also A.3.
longitudinal hull girder bending (including bending
new E.1.2.2.2
due to impact loads), horizontal bending, torsion and
local loads and also under consideration of the buck- 2.3 For ships classed for the restricted service
ling strength. area RSA (20), special consideration may be given to

new E.1.2.1.4 a further reduction of the minimum section modulus in
connection with wave height restrictions.
1.3 The required section moduli shall be fulfilled
inside and outside 0,4 L amidships in general. Outside 3. Midship section moment of inertia
0,4 L particular attention shall be paid for the follow- The moment of inertia related to the horizontal axis is
ing locations:
not to be less than:
– in way of the forward end of the engine room
L
– in way of the forward end of the foremost cargo Iy = 3 ⋅ 10−2 ⋅ W ⋅ [m 4 ]
k
hold
W = see 1. and/or 2.1, the greater value is to be
– at any locations where there are significant
taken
changes in hull cross section

new E.1.2.3
– at any locations where there are changes in the
framing system
4. Calculation of section moduli
– for ships with large deck openings such as con-
tainerships, locations at or near 0,25 L and 4.1 The bottom section modulus WB and the
0,75 L deck section modulus WD are to be determined by the
– for ships with cargo holds aft of the superstruc- following formulae:
ture, deckhouse or engine room, locations in
way of the aft end of the aft-most hold and in Iy
WB = [m3 ]
way of the aft end of the superstructure, deck- eB
house or engine room
Iy [m3 ]

new E.1.2.1.3 WD =
eD
2. Minimum midship section modulus
Continuous structural elements above eD (e.g. trunks,
longitudinal hatch coamings, decks with a large cam-
2.1 The section modulus related to deck and bot-
ber, longitudinal stiffeners and longitudinal girders
tom is not to be less than the following minimum value:
arranged above deck, bulwarks contributing to longi-
Wmin = k ⋅ co ⋅ L2 ⋅ B ⋅ ( CB + 0,7) ⋅ cRS ⋅ 10−6 [m3 ] tudinal strength etc.) may be considered when deter-
mining the section modulus, provided they have shear
cRS = service range coefficient connection with the hull and are effectively supported
by longitudinal bulkheads or by rigid longitudinal or
= 1,0 for unlimited service range transverse deep girders.
= 0,95 for restricted service area RSA (200) The fictitious deck section modulus is then to be de-
= 0,85 for restricted service area RSA (50) termined by the following formula:
= 0,80 for restricted service area RSA (20) Iy
WD' = [m3 ]
= 0,75 for restricted service area RSA (SW) e'D
c0 = according to Section 4, A.2.2 for unlimited
 y
service range (cRW = 1,0) e'D = z ⋅  0,9 + 0,2 ⋅  [m]
 B

new E.1.2.2.1
z = distance [m] from neutral axis of the cross
2.2 The scantlings of all continuous longitudinal section considered to top of continuous
members based on the minimum section modulus strength member
requirement are to be maintained within 0,4 L amid- y = distance [m] from centre line to top of con-
ships. tinuous strength member
However, in special cases, based on consideration of It is assumed that e'D > eD.
type of ship, hull form and loading conditions, the
I - Part 1 Section 5 C Longitudinal Strength Chapter 1
GL 2012 Page 5–11

For ships with multi-hatchways, see 5. 5. Ships with multi-hatchways

new E.1.1.1.2
new E.1.1.2

4.2 When calculating the section modulus, open- 5.1 For the determination of section moduli,
ings of continuous longitudinal strength members 100 % effectivity of the longitudinal hatchway girders
shall be taken into account. between the hatchways may be assumed, if an effec-
tive attachment of these girders is given.
Large openings, i.e. openings exceeding 2,5 m in
length or 1,2 m in breadth and scallops, where scallop- 5.2 An effective attachment of the longitudinal
welding is applied, are always to be deducted from the hatchway girders has to fulfil the following condition:
sectional areas used in the section modulus calcula-
tion. The longitudinal displacement fL of the point of at-
tachment due to action of a standard longitudinal force
Smaller openings (manholes, lightening holes, single
PL is not to exceed
scallops in way of seams etc.) need not be deducted
provided that the sum of their breadths or shadow area ℓ
breadths in one transverse section is not reducing the fL = [mm]
20
section modulus at deck or bottom by more than 3 %
and provided that the height of lightening holes, drain-
ing holes and single scallops in longitudinals or longi- ℓ = length of transverse hatchway girder according
tudinal girders does not exceed 25 % of the web depth, to Fig. 5.7 [m]
for scallops 75 mm at most (see Fig. 5.7).
PL = 10 ⋅ A LG [kN]
A deduction-free sum of smaller opening breadths in
one transverse section in the bottom or deck area of
0,06 ⋅ (B – Σb) may be considered equivalent to the
above reduction in section modulus by 3 %.
B = breadth of the ship at the considered trans-
verse section
Σb = sum of breadth of large openings [m]

The shadow area will be obtained by drawing two

tangent lines with an opening angle of 30°, see Fig.
5.7. PL

new E.1.1.1.1

loaded empty
hold hold fL
D Q1
D Q2
Fig. 5.8 Ship with multi-hatchways
ALG = entire cross sectional area of the longitudinal
hatchway girder [cm2]
corrected shear
See also Fig. 5.8.
force curve
Where the longitudinal displacement exceeds
conventional
shear force curve fL > ℓ/20, special calculation of the effectivity of the
D Q1
D Q2 longitudinal hatchway girders may be required.

Note
Fig. 5.7 Shadow area Upon request GL will carry out the relevant direct
calculations.
Note
In case of large openings local strengthening may be 5.3 For the permissible combined stress see Sec-
required which will be considered in each individual tion 10, E.3.
case (see also Section 7, A.3.1).

new E.1.1.1.1 Note
Chapter 1 Section 5 C Longitudinal Strength I - Part 1
Page 5–12 GL 2012

6. Shear strength used in the damage stability calculations (see

Section 28).
The shear stress in longitudinal structures due to the
vertical transverse forces QT acc. to E.2. shall not ex- cs = stress factor according to 1.1
ceed 110/k N/mm2. MU = ultimate vertical bending moments of the ship's
For ships with large deck openings and/or for ships transverse section in the hogging (MU,H) and
with large static torsional moments, also the shear sagging (MU,S) conditions [kNm]. See 8.2.1.
stresses due to MSTmax have to be considered ad- MUf = ultimate vertical bending moments of the ship's
versely, i.e. increasing the stress level. damaged transverse section in the hogging
(MUf,H) and sagging (MUf,S) conditions [kNm].
The shear stresses are to be determined according to
If no assumptions regarding the extent of
D.3.
damage are prescribed, MUf = κdM ⋅ MU, where

new E.2 κdM is a reduction factor for the ultimate mo-
ments in damaged conditions (κdM ≤ 1). The
7. Proof of buckling strength reduction factor κdM equals 1 unless a smaller
value is specified by the owner or shipyard.
All longitudinal hull structural elements subjected to
compressive stresses resulting from MT according to
new E.5.2
E.1. and QT according to E.2. are to be examined for
sufficient resistance to buckling according to Section 8.2.1 Progressive collapse analysis
3, F. For this purpose the following load combinations A progressive collapse analysis is to be used to calcu-
are to be investigated: late the ultimate vertical bending moments of a ship's
transverse section. The procedure is to be based on a
– MT and 0,7 ⋅ QT
simplified incremental-iterative approach where the
– 0,7 ⋅ MT and QT capacities are defined as the peaks of the resulting
moment-curvature curve (M-χ) in hogging (positive)
The stresses are to be calculated according to D. and sagging (negative) conditions, i.e. χ is the hull

new E.4 girder curvature [1/m]. See Fig. 5.9.
The main steps to be used in the incremental-iterative
8. Ultimate load calculation of the ship's approach are summarised as follows:
transverse sections
Step 1 The ship's transverse section is to be divided
8.1 In extreme conditions, larger loads than re- into plate-stiffener combinations (see 8.2.2.2
ferred to in B. may occur. Therefore, dimensioning of (a)) and hard corners (see 8.2.2.2(b)).
longitudinal structures is to be verified by proving the
M
ultimate capacity according to 8.2 and 8.3. The calcu- Hogging
lations are to include those structural elements con- M U,H
tributing to the hull girder longitudinal strength and
are to be based on gross scantlings.
The following safety factors are to be assumed: c
γR = 1,20
γWV = 1,20 Sagging
M U,S

new E.5.1

8.2 Ultimate vertical bending moment Fig. 5.9 Moment-curvature curve

γ WV ⋅ M WV MU
M SW + ≤ Step 2 The average stress – average strain relationships
cs γR σCRk-ε for all structural elements (i.e. stiffener-
plate combinations and hard corners) are to be
0,8 ⋅ γ WV ⋅ M WV M Uf defined, where the subscript k refers to the
M SWf + ≤
cs γR modes 0, 1, 2, 3 or 4, as applicable (see 8.2.2).
Step 3 The initial and incremental value of curvature
MSWf = maximum vertical still water bending moment
in flooded conditions [kNm]. For a transverse ∆χ is to be defined by the following formula:
section under consideration, the most severe R eH
levels of vertical still water bending moments 0.05
∆χ = E
are to be selected from those cases of flooding z D − z NA,e
I - Part 1 Section 5 C Longitudinal Strength Chapter 1
GL 2012 Page 5–13

zD = z co-ordinate of strength deck at side s CR k

[m] (see also Fig. 5.1) s CRk,max Compressed
zNA,e = z co-ordinate of elastic neutral axis for elements (+e)
the ship's transverse section [m]

Step 4 For the value of curvature, χj = χj-1 + ∆χ, the

average strain εΕi,j = χj zi and corresponding e
average stress σi,j is to be defined for each Elongated
elements (-e)
structural element i (see 8.2.2). For structural
R eH
elements under tension, σi,j = σCR0 (see
8.2.2.1). For plate-stiffener combinations un-
Fig. 5.10 Typical average stress - average strain curve
der compression, σi,j = minimum [σCR1, σCR2,
σCR3] (see 8.2.2.2 (a)). For hard corners under 8.2.2.1 Negative strain (σCR0-ε)
compression, σi,j = σCR4 (see 8.2.2.2 (b)).
The portion of the curve corresponding to negative
zi = z co-ordinate of ith structural element strain (i.e. tension) is in every case to be based on
[m] relative to basis, see also Fig. 5.11 elasto-plastic behaviour (i.e. material yielding) accord-
ing to the following:
Step 5 For the value of curvature, χj = χj-1 + ∆χ, the
height of the neutral axis zNA,j is to be deter- σCR0 = ΦR eH [N / mm 2 ]
mined iteratively through force equilibrium
over the ship's transverse section: Φ = edge function
m n
= –1 for ε < –1
∑ Ai σi, j = ∑ Ai σi, j = ε for –1 ≤ ε ≤ 0
i =1 i =1
ε = relative strain
m is the number of structural elements located
above zNA,j εE
=
εY
n is the number of structural elements located
below zNA,j εE = element strain
th
Ai = cross-sectional area of i plate-stiffener εY = strain at yield stress in the element
combination or hard corner
R eH
Step 6 For the value of curvature, χj = χj-1 + ∆χ, the cor- =
E
responding bending moment is to be calculated
by summing the contributions of all structural
new E.5.2.2.1
elements within the ship's transverse section:
8.2.2.2 Positive strain
M U, j = ∑ σi, j A i (z NA, j − z i )
The portion of the curve corresponding to positive
strain (i.e. compression) is to be based on some mode
Steps 4 through 6 are to be repeated for increasing of collapse behaviour (i.e. buckling) for two types of
increments of curvature until the peaks in the M-χ structural elements; (a) plate-stiffener combinations
curve are well defined. The ultimate vertical bending and (b) hard corners. See Fig. 5.11.
moments MU,H and MU,S are to be taken as the peak
values of the M-χ curve. Plate-Stiffener 3 Plate Hard
Combination Corner

new E.5.2.1 (8.2.2.2(a)) (8.2.2.2(b))
b1 b2 b1 b2
8.2.2 Average stress - average strain curves b3
A typical average stress – average strain curve σCRk-ε zi zi
for a structural element within a ship's transverse sec-
tion is shown in Fig. 5.10, where the subscript k refers
to the modes 0, 1, 2, 3 or 4, as applicable.
Fig. 5.11 Structural elements

new E.5.2.2
(a) Plate-stiffener combinations
(σCR1-ε, σCR2-ε, σCR3-ε)
Plate-stiffener combinations are comprised of a single
stiffener together with the attached plating from adjacent
plate fields. Under positive strain, three average stress
Chapter 1 Section 5 C Longitudinal Strength I - Part 1
Page 5–14 GL 2012

– average strain curves are to be defined for each plate- ling of plate-stiffener combinations is described ac-
stiffener combination based on beam column buckling cording to the following:
(σCR1-ε), torsional buckling (σCR2-ε) and web/flange
local buckling (σCR3-ε). AStif κ Τ + b m,1t1 / 2 + b m,2 t 2 / 2
σ CR 2 = Φ R eH
AStif + b1 t1 / 2 + b 2 t 2 / 2
( i ) Beam column buckling σCR1-ε
The positive strain portion of the average stress – κΤ = reduction factor according to Section 3, F.3.3.
average strain curve σCR1-ε based on beam column
(iii) Web/flange local buckling σCR3-ε
buckling of plate-stiffener combinations is described
according to the following: The positive strain portion of the average stress –
average strain curve σCR3-ε based on web/flange local
AStif + b m,1t1 / 2 + bm,2 t 2 / 2 buckling of plate-stiffener combinations is described
σCR1 = ΦR eH κ BC
AStif + b1t1 / 2 + b 2 t 2 / 2 according to the following:
h w,m t w + bf ,m t f + b m,1t1 / 2 + bm,2 t 2 / 2
Φ = edge function σCR3 = ΦR eH
h w t w + bf t f + b1t1 / 2 + b 2 t 2 / 2
= ε for 0 ≤ ε ≤ 1
hw,m, bf,m= effective width of web/flange plating [mm]
= 1 for ε > 1 according to Section 3, F.2.2 (generally based
on Load Case 3 of Table 3.3 for flat bars and
κBC = reduction factor flanges, otherwise Load Case 1) where the refer-
= 1 for λK ≤ 0,2 ence degree of slenderness is to be defined as

1 εE
= for λK > 0,2 λ=
2 2 2
kD + kD − λK t
0,9   K
b
εE a 2 A x
λK = 2
⋅10−4 hw = web height [mm]
π Ix
tw = web thickness [mm]
kD = (1 + 0,21 (λK – 0,2) + λK2) / 2
bf = flange breadth, where applicable [mm]
a = length of stiffener [mm] tf = flange thickness, where applicable [mm]
Ax = sectional area of stiffener with attached shell
plating of breadth (bm,1/2 + bm,2/2) [mm2] (b) Hard corners (σCR4-ε)
Ix = moment of inertia of stiffener with attached Hard corners are sturdy structural elements comprised of
shell plating of breadth (bm,1/2 + bm,2/2) [cm4] plates not lying in the same plane. Bilge strakes (i.e. one
curved plate), sheer strake-deck stringer connections (i.e.
bm,1, bm,2 = effective widths of single plate fields on two plane plates) and bulkhead-deck connections (i.e. three
sides 1 and 2 of stiffener [mm] according to plane plates) are typical hard corners. Under positive strain,
Section 3, F.2.2, in general based on Load single average stress – average strain curves are to be de-
Case 1 of Table 3.3, where the reference de- fined for hard corners based on plate buckling (σCR4-ε).
gree of slenderness is to be defined as
( i ) Plate buckling σCR4-ε
εE n
λ=
t
2 ∑ b m,i t i
0,9   K σCR 4 = ΦR eH i =1
b n
∑ bi t i
i =1
b1, b2 = breadths of single plate fields on sides 1 and
2 of stiffener [mm], see also Fig. 5.11 bm,i = effective widths of single plate fields [mm]
according to Section 3, F.2.2, as applicable,
t1, t2 = thicknesses of single plate fields on sides 1
in general based on applicable Load Cases in
and 2 of stiffener [mm] Table 3.3 and Table 3.4, where the reference
AStif = sectional area of the stiffener without at- degree of slenderness is to be defined as
tached plating [mm2]
εE
(ii) Torsional buckling σCR2-ε λ= 2
t
The positive strain portion of the average stress – 0,9   K
b
average strain curve σCR2-ε based on torsional buck-
I - Part 1 Section 5 D Longitudinal Strength Chapter 1
GL 2012 Page 5–15

bi = breadth of single plate fields [mm], see also – for plates as membrane stresses
Fig. 5.11
– for longitudinal profiles and longitudinal
ti = thickness of single plate fields [mm] girders in the bar axis
n = number of plates comprising hard corner – shear stresses τL in the plate level

new E.5.2.2.2

new D.2.1
8.3 Ultimate vertical shear force The stresses σL and τL are to be considered in the for-
mulas for dimensioning of plate thicknesses (Section
γ WV ⋅ Q WV Q 6, B.1. and C.1. and Section 12, B.1.), longitudinals
QSW + ≤ U
cs γR (Section 9, B.2.) and grillage systems (Section 8, B.8.
and Section 10, E.2.).
0,8 ⋅ γ WV ⋅ Q WV Q
QSWf + ≤ Uf The calculation of the stresses can be carried out by an
cs γR analysis of the complete hull. If no complete hull
analysis is carried out, the most unfavourable values
QSWf = maximum vertical still water shear force in of the stress combinations according to Table 5.3 are
flooded conditions [kN]. For a transverse sec- to be taken for σL and τL respectively.
tion under consideration, the most severe levels
of vertical still water shear forces are to be se-
new D.2.2
lected from those cases of flooding used in the
damage stability calculations (see Section 28). The formulae in Table 5.3 contain σSW, σWV, σWH,
σST and σWT according to 2. and τSW, τWV, τWH,
cs = stress factor according to 1.1 τST and τWT according to 3. as well as:
QU = ultimate vertical shear force of the ship's fF = weighting factor for the simultaneousness of
transverse section [kN] global and local loads
1 q = 0,8 for dimensioning of longitudinal struc-
= ⋅ ∑ κ τi ⋅ bi .t i ⋅ R eH,i tures according to Sections 3 and 6 to 12
1000 ⋅ 3 i =1
x  x
q = number of shear force transmitting plate fields = 0, 75 + ⋅ 1 − 
(in general, these are only the vertical plate L  L
fields of the ship's transverse section, e.g. shell for fatigue strength calculations acc. to Sec-
and longitudinal bulkhead plate fields) tion 20
τi = reduction factor of the ith plate field according fQ = probability factor acc. to Section 4, Table 4.2
to Section 3, F.2.1.
fQmin = 0,75 for Q = 10–6
bi = breadth of the ith plate field [mm]
ti = thickness of the ith plate field [mm]
new D.2.3.1

QUf = ultimate vertical shear force of the ship's Note

undamaged transverse section [kN]. If no as-
sumptions regarding the extent of damage are fQ is a function of the design lifetime. For a lifetime of
prescribed, QUf = κdM·QU, where κdM is a re- n > 20 years, fQ may be determined by the following
duction factor for the ultimate force in dam- formula for a straight-line spectrum of seaway-
aged conditions (κdM ≤ 1). induced stress ranges:
 2 ⋅ 10− 5 

new E.5.3 fQ = − 0,125 ⋅ log  
 n 
 

new D.2.3.1 Note
D. Design Stresses
For greatest vertical wave bending moment:
1. General σ'WV = ( 0, 43 + C ) ⋅ σ WVhog
Design stresses for the purpose of this rule are global τ'WV = ( 0, 43 + C ) ⋅ τWVhog
load stresses, which are acting:
– as normal stresses σL in ship's longitudinal di-
rection:
Chapter 1 Section 5 D Longitudinal Strength I - Part 1
Page 5–16 GL 2012

Table 5.3 Load cases and stress combinations

Load case Design stresses σL, τL

σL1a = σSW + σST + f Q ⋅ σ WV
L1a
τL1a = 0, 7 ⋅ τSW + τST + 0, 7 ⋅ fQ ⋅ τ WV

σL1 b = 0, 7 ⋅ σSW + σST + 0, 7 ⋅ f Q ⋅ σ WV

L1b
τL1 b = τSW + τST + f Q ⋅ τ WV

σL2 a = σSW + σST + fQ ⋅ ( 0, 6 ⋅ σWV + σWH )

L2a
τL2 a = 0, 7 ⋅ τSW + τST + 0, 7 ⋅ fQ ⋅ ( 0, 6 ⋅ τWV + τWH )

σL2 b = 0, 7 ⋅ σSW + σST + 0, 7 ⋅ f Q ⋅ ( 0,6 ⋅ σ WV + σWH )

L2b
τL2 b = τSW + τST + fQ ⋅ ( 0, 6 ⋅ τWV + τWH )

σL3 a = f F ⋅ σSW + σST + f Q ⋅ σ'WV + σ WH + σ WT 

( )
 
L3a
τL3 a = f F ⋅ 0, 7 ⋅ τSW + τST + f Q ⋅  0, 7 ⋅ τ'WV + τWH + τWT 
{ ( ) }
 

σL3 b = f ⋅ {0, 7 ⋅ σ + σ + f ⋅ 0,7 ⋅ ( σ '

+ σ WH + σ WT 
) }
F SW ST
Q WV

L3b
τL3 b = f F ⋅  τSW + τST + f ⋅(τ '
+τ + τ )
 Q WV WH  WT

L1a, b = Load caused by vertical bending and static torsional moment.

L2a, b = Load caused by vertical and horizontal bending moment as well as static torsional moment.
L3a, b = Load caused by vertical and horizontal bending moment as well as static and wave induced torsional moment.
For smallest vertical wave bending moment:
1.1 Buckling strength
σ 'WV =  0,43 + C ⋅ ( 0,5 - C )  ⋅ σ WVhog
For structures loaded by compression and/or shear
+ C ⋅ ( 0,43 + C ) ⋅ σ WVsag forces, sufficient buckling strength according to
Section 3, F. is to be proved.
τ 'WV =  0, 43 + C ⋅ ( 0,5 − C )  ⋅ τ WVhog

new Section 3, D.1
+ C ⋅ ( 0, 43 + C ) ⋅ τ WVsag
1.2 Permissible stresses

x 
2 The equivalent stress from σL and τL is not to exceed
C =  − 0,5  the following value:
L 
190

new D.2.3.3 σv = σ L2 + 3 ⋅ τL2 ≤ [N / mm 2 ]
k
Note
new E.2
For the preliminary determination of the scantlings, it
1.3 Structural design
is generally sufficient to consider load case 1, assum-
ing the simultaneous presence of σL1a and τL1b, but 1.3.1 In general, longitudinal structures are to be de-
disregarding stresses due to torsion. signed such, that they run through transverse structures
continuously. Major discontinuities have to be avoided.

new D.2.3.1 Note

new Section 3, E.2.4
The stress components (with the proper signs: tension
positive, compression negative) are to be added such, If longitudinal structures are to be staggered, sufficient
that for σL and τL extreme values are resulting. shifting elements shall be provided.

new Section 3, E.2.5

new D.2.3.2
I - Part 1 Section 5 D Longitudinal Strength Chapter 1
GL 2012 Page 5–17

1.3.2 The required welding details and classifying
new D.2.4.1.2

of notches result from the fatigue strength analysis
according to Section 20. 2.3 Normal stresses from torsion of the ship's

new E.3.1 hull
When assessing the cross sectional properties the
Within the upper and lower hull girder flange, the
effect of wide deck strips between hatches constrain-
detail categories for the welded joints (see Section 20,
ing the torsion may be considered, e.g. by equivalent
Table 20.3) shall not be less than
plates at the deck level having the same shear defor-
(MWVhog − MWVsag ) ⋅ ez mation as the relevant deck strips.
∆σRmin = [N/ mm2 ]
new D.2.4.1.3
(4110 − 29 ⋅ n) ⋅ Iy

MWVhog, MWVsag = vertical wave bending moment 2.3.1 statical from MSTmax:
for hogging and sagging ac- For a distribution of the torsional moments according
cording to B.3.1 to B.2.2.2, the stresses can be calculated as follows:
n = design lifetime of the ship
≥ 20 [years] 0,65⋅ CTor ⋅ MSTmax ⋅ ωi  2 
σST = ⋅ 1 −  [N/ mm2 ]
λ ⋅ Iω ⋅103  ea
1 

new E.3.2  + 
MSTmax = max. static torsional moment according to
2. Normal stresses in the ship's longitudinal B.2.2.2
direction
CTor, Iω, ωi, λ, e, a, ℓc, Cc, xA see 2.3.2.
2.1 Normal stresses from vertical bending For other distributions the stresses have to be deter-
moments mined by direct calculations.
2.1.1 statical from MSW:
new D.2.4.1.3
MSW ⋅ ez 2.3.2 dynamical from MWTmax:
σSW = 3
[N / mm2 ]
I y ⋅ 10
CTor ⋅ MWT max ⋅ωi  2 
σWT = ⋅ 1 −  [N / mm2 ]
3 a
MSW = still water bending moment according to A.5. λ ⋅ Iω ⋅10  e +1 
at the position x/L
MWTmax = according to B.3.5

new D.2.4.1.1
x x
2.1.2 dynamical from MWV: CTor = 4⋅ ( )
CB − 0,1 ⋅
L
for 0 ≤
L
< 0, 25

M WV ⋅ ez x
σ WV = [N / mm 2 ] = CB − 0,1 for 0,25 ≤ ≤ 0,65
3
I y ⋅ 10 L

new D.2.4.1.1 CB − 0,1  x  x

= ⋅ 1 −  for 0, 65 < ≤ 1
0,35  L  L
2.2 Normal stresses due to horizontal bending
moments Iω = sectorial moment of inertia [m6] of the ship's
transverse section at the position x/L
dynamical from MWH:
ωi = sectorial coordinate [m2] of the structure
M WH ⋅ e y considered
σ WH = − [N / mm 2 ]  = warping value
3
Iz ⋅ 10
IT
MWH = horizontal wave bending moment according = [1 m]
2, 6 ⋅ Iω
to B.3.3 at the position x/L
Iz = moment of inertia [m4] of the transverse ship IT = torsional moment of inertia [m4] of the ship's
section considered around the vertical axis at transverse section at the position x/L
the position x/L e = Euler number (e = 2,718...)
ey = horizontal distance of the structure consid- a = λ ⋅ ℓc
ered from the vertical, neutral axis [m]
ey is positive at the port side, ℓc = characteristical torsion length [m]
negative at the starboard side
Chapter 1 Section 5 D Longitudinal Strength I - Part 1
Page 5–18 GL 2012

L t = thickness of side shell plating respectively of

= 0,5 ⋅ L ⋅ Cc for <6 the plating of the longitudinal bulkhead con-
B
sidered [mm]
 L L
= 1, 22 − 0,12 ⋅  ⋅ L ⋅ Cc for ≤ 8,5 α = 0 for ships without longitudinal bulkheads
 B  B
If two longitudinal bulkheads are arranged:
L
= 0,2 ⋅ L ⋅ Cc for > 8,5 AS
B α = 0,16 + 0,08 ⋅
AL
ℓc, min = L – xA for the longitudinal bulkhead
xA  x  x AS
Cc = 0,8 − +  0,5 + 2,5 ⋅ A ⋅ = 0,34 − 0, 08 ⋅
L  L  L AL
for the shell
x x
for 0 ≤ < 0, 4 and 0 ≤ A ≤ 0, 4 AS = area of cross section of the shell within depth
L L
H [m2]
x
= 1 for 0, 4 ≤ ≤ 0,55 AL = area of cross section of longitudinal bulkhead
L
within depth H [m2]
1 x  x
= 1− ⋅  − 0,55  for 0,55 < ≤1 For ships of normal shape and construction, the ratio
0, 45  L  L Sy/Iy determined for the midship section can be used
for all cross sections.
xA = 0 for ships without cargo hatches
= distance [m] between the aft end of the length
new D.2.4.2.1
L and the aft edge of the hatch forward of the
engine room front bulkhead on ships with 3.2 Shear stresses due to horizontal shear forces
cargo hatches, see also Fig. 5.13
3. is to be applied to correspondingly.

new D.2.4.1.3

new D.2.4.2.2
3. Shear stresses
3.3 Shear stresses due to torsional moments
Shear stress distribution shall be calculated by calcula-
tion procedures approved by GL. For ships with multi- statical from MSTmax:
cell transverse cross sections (e. g. double hull ships),
the use of such a calculation procedure, especially For a distribution of the torsional moments according
with non-uniform distribution of the load over the to B.2.2.2, the stresses can be calculated as follows:
ship's transverse section, may be stipulated.
Sω i

new D.2.4.2 τST = 0,65 ⋅ CTor ⋅ MST max ⋅ [N / mm2 ]
Iω ⋅ t i
3.1 Shear stresses due to vertical shear forces
CTor = according to D.2.3.1
As a first approximation for ships without longitudinal
bulkheads or with 2 longitudinal bulkheads, the distri- MSTmax = according to B.2.2.2
bution of the shear stress in the shell and in the longi- MWTmax = according to B.3.5
tudinal bulkheads can be calculated with the following
formula: Iω = according to D.2.3.1
statical from QSW: Sω i = statical sector moment [m4] of the struc-
ture considered
QSW ⋅ Sy ( z )
τSW = ⋅ ( 0,5 − α ) [N / mm 2 ] t¡ = thickness [mm] of the plate considered
Iy ⋅ t
For other distributions the stresses have to be deter-
dynamical from QWV:
mined by direct calculations.
QWV ⋅ Sy ( z ) dynamical from MWTmax:
τWV = ⋅ ( 0,5 − α ) [N / mm2 ]
Iy ⋅ t
Sωi
τWT = CTor ⋅ MWTmax ⋅ [N / mm2 ]
Sy(z) = first moment of the sectional area considered [m3], Iω ⋅ t i
above or below, respectively, the level z consid-
ered, and related to the horizontal, neutral axis
new D.2.4.2.3
I - Part 1 Section 5 E Longitudinal Strength Chapter 1
GL 2012 Page 5–19

E. Permissible Still Water Loads τ = permissible shear stress [N/mm2]

QWV = according to B.3.2
1. Vertical bending moments
For harbour and offshore terminal conditions, see 1.
The permissible still water bending moments for any
section within the length L are to be determined by the
new E.6.2.1
following formulae:
2.1 Correction of the shear force curve
MSW = MT − M WV [kNm] In cases with empty cargo holds, the conventional shear
force curve may be corrected according to the direct
MWV = according to B.3.1 load transmission by the longitudinal bottom structure
For harbour- and offshore terminal conditions the wave at the transverse bulkheads. See also Fig. 5.12.
loads may be multiplied with the following factors:
newE.6.2.2
– harbour conditions (normally): 0,1
loaded empty
– offshore terminal conditions: 0,5 hold hold
D Q1
From the following two values for MT: D Q2
1
MT = σD ⋅ WD(a) ⋅ 103 [kNm]
fr

1
= σB ⋅ WB(a) ⋅ 103 [kNm] corrected shear
fr force curve

the smaller one is to be taken. conventional

shear force curve
WD(a), WB(a) = actual section modulus in the deck D Q1
D Q2
or bottom, respectively
σ D , σ 'D = longitudinal bending stress [N/mm2]
Fig. 5.12 Correction of the shear force curve
for the ship's upper hull girder flange
= σSW + σWV 2.2 The supporting forces of the bottom grillage at
the transverse bulkheads may either be determined by
σB = longitudinal bending stress [N/mm2] direct calculation or by approximation, according to 2.3.
for the ship's lower hull girder flange
new E.6.2.3
= σSW + σWV
2.3 The sum of the supporting forces of the bot-
σSW, σWV longitudinal stress according to D.2. tom grillage at the aft or forward boundary bulkhead
of the hold considered may be determined by the fol-
fr = 1,0 (in general) lowing formulae:
= according to F.2. for ships with large
deck openings ∆Q = u ⋅ P − v ⋅ T* [kN]
In the range between x/L = 0,3 and x/L = 0,7 the per- P = mass of cargo or ballast [t] in the hold con-
missible still water bending moment shall generally sidered, including any contents of bottom
not exceed the value obtained for x/L = 0,5. tanks within the flat part of the double bottom

new E.6.1 T* = draught [m] at mid length of the cargo hold

2. Vertical shear forces u, v = correction coefficients for cargo and buoy-

ancy as follows:
The permissible still water shear forces for any cross
section within the length L are to be determined by the 10 ⋅ κ ⋅ ℓ ⋅ b ⋅ h
u = [kN / t]
following formula: V
QSW = QT − Q WV [kN] v = 10 ⋅ κ ⋅ ℓ ⋅ b [kN / m]

QT = permissible total shear force [kN], for which B

κ =
the permissible shear stress τ = τSW + τWV 2,3 ( B + ℓ )
will be reached but not exceeded at any point
of the section considered ℓ = length of the flat part of the double bottom [m]
Chapter 1 Section 5 F Longitudinal Strength I - Part 1
Page 5–20 GL 2012

b = breadth of the flat part of the double bottom [m] bL = breadth of hatchway, in case of multi-
hatchways, bL is the sum of the individual
h = vertical distance between inner bottom and top
of hatch coaming [m] hatchway-breadths

V = volume of cargo hold including volume en- ℓL = length of hatchway

closed by hatch coaming [m3]
BM = breadth of deck measured at the mid length of

new E.6.2.3 hatchway

3. Static torsional moments ℓM = distance between centres of transverse deck

strips at each end of hatchway. Where there is
The permissible static torsional moments have to be no further hatchway beyond the one under
determined on the basis of the design stresses in Table consideration, ℓM will be specially considered.
5.3. together with the formula in D.2.3.1.

new E.6.3.1
new E.8.1.2

3.1 For ships with torsional moments according 2. Guidance values for the determination of
to B.2. it has to be proved by means of the loading the section modulus
computer, that the maximum permissible values are
exceeded at no location. Excess values are permissi- The section moduli of the transverse sections of the
ble, if the actual torsional moments at the adjacent ship are to be determined according to C.1. and C.2.
calculation points are correspondingly less than the
permissible values. The factor fr amounts to:

new E.6.3.2 σL1

fr =
σSW + 0, 75 ⋅ σ WV
3.2 Unless shown by a particular proof, during
loading and unloading the static torsional moments
shall not be higher than 75 % of the wave induced σL1, σSW, σWV according to D. for the ship's upper
torsional moment according to B.3.5. and lower hull girder flange respectively. The greater
value is to be taken.

new E.6.3.3
The calculation of the factor fr may be dispensed with,
if fr is selected according to Fig. 5.13.

F. Guidance Values for Large Deck Openings
new E.8.2

1. General fr
1,10
1.1 Displacements of the upper hull girder flange 1,08
mainly caused by torsional loads, induce additional 1,05
local bending moments and forces acting in the deck
strips. These moments act about the z-axis, see Fig. x/L
1,00
5.1. After consultation with GL stresses resulting from 0,05 1,0
that have to be calculated for longitudinal and trans- 0,15 0,3
verse girders and to be taken into account for the de- xA
sign.
The calculation of these stresses can be dispensed
with, if the guidance values according to 2. and 3. are
observed.

new E.8.1.1

1.2 A ship is regarded as one with large deck

openings if one of the following conditions applies to cu
one or more hatch openings: 1,0
bL
cA

– > 0,6 0
BM x-xA 0,75 1,0

ℓL
– > 0, 7
ℓM Fig. 5.13 Correction factor fr and distribution
factor cu
I - Part 1 Section 5 G Longitudinal Strength Chapter 1
GL 2012 Page 5–21

3. Guidance values for the design of trans- MSTmax, MWTmax acc. to B.2.2.2 or B.3.5, respectively
verse box girders of container ships
cu = distribution factor according to Fig. 5.13
The scantlings are to be determined by using the
following design criteria: cA = value for cu at the aft part of the open region,
– support forces of hatch covers, see Section 17, see also Fig. 5.13
B.4.5 – B.4.7.
 L   3 ⋅ xA 
= 1, 25 − ⋅ 1, 6 − ≤ 1, 0
– support forces of the containers stowed in the 

400   L 
hold place (e.g. due to longitudinal acceleration)
– stresses due to the torsional deformations of the hull xA = according to D.2.3.1; for xA no smaller value
than 0,15 L and no greater value than 0,3 L is
– stresses resulting from the water pressure, if the to be taken.
transverse box girder forms part of a watertight
bulkhead, see Section 11
new E.8.4
In general the plate thickness shall not be less than ob-
tained from the following formulae, see also Fig. 5.14:
G. Bulk Carriers
t1 = L [mm] or
1. General
= 0,5 ⋅ t 0 [mm]
In addition to the requirements of B., for all bulk carriers
t0 = thickness of longitudinal hatch coaming or of the with the Notation BC-A or BC-B according to Section
uppermost strake of the longitudinal bulkhead 23, F.2.1, the longitudinal strength is to be checked to be
adequate for specified flooded conditions, in each of the
t2 = 0,85 ⋅ L [mm] or cargo and ballast conditions considered in the intact
= 12 ⋅ a [mm] longitudinal strength calculations. The loading condi-
tions ''har-bour'', ''docking, afloat'', ''loading and unload-
a = spacing of stiffeners [m] ing tran-sitory conditions'' as well as ''ballast water ex-
change'' need not be considered.
The larger value of t1 and t2 is to be taken. L needs not
be taken greater than 200 m. The required moment of inertia according to C.3. and
the strength of local structural members are excluded
For coamings on the open deck see also Section 17, B.1. from this proof.

new E.8.3
new Section 23, C.2.2.1
t0
For accessibility see Section 1, D.1.
t2 t1
2. Flooding criteria

t2 t1 To calculate the weight of ingressing water, the fol-

t1 lowing assumptions are to be made:
– The permeability of empty cargo spaces and
volume left in loaded cargo spaces above any
cargo is to be taken as 0,95.
Fig. 5.14 Plate thickness of the transverse box
girder – Appropriate permeabilities and bulk densities are
to be used for any cargo carried. For iron ore, a
minimum permeability of 0,3 with a corresponding
4. Guidance values for the displacements of bulk density of 3,0 t/m3 is to be used. For cement, a
the upper hull girder flange of the ship minimum permeability of 0,3 with a correspond-
In general, the relative displacement ∆u between the ing bulk density of 1,3 t/m3 is to be used. In this re-
ship sides is to be determined by direct calculations. spect, "permeability" for solid bulk cargo means
For the dimensioning of hatch cover bearings and seals, the ratio of the floodable volume between the
the following value may be used for the displacement: cargo parts to the gross volume of the bulk cargo.

6  L  – For packed cargo conditions (such as steel mill

∆u = ⋅ ( MSTmax + MWTmax ) ⋅ 1 −
5  products), the actual density of the cargo should
10  450  be used. The permeability has to be harmonized
 L2  case by case (pipes, flat steel, coils etc.) with GL.
⋅ 4 + 0,1 2  ⋅ cu + 20 [mm]
 B 
new Section 23, C.2.2.2
Chapter 1 Section 5 G Longitudinal Strength I - Part 1
Page 5–22 GL 2012

hull spacing exceeds 1 000 mm, measured vertically to

3. Flooding conditions the shell at any location of the cargo hold length.
The wave induced vertical bending moments and shear
forces in the flooded conditions are assumed to be equal
Each cargo hold is to be considered individually flooded to 80 % of the wave loads, as given in B.3.1. and B.3.2.
up to the equilibrium waterline. This does not apply for
cargo holds of double hull construction where the double
new Section 23, C.2.2.3
I - Part 1 Section 6 B Shell Structures Chapter 1
GL 2012 Page 6–1

Section 6

Shell Structures

A. General, Definitions tK = corrosion addition according to Section 3, K.

1. General

new A.2
1.1 The application of the design formulae given
in B.1.2 and C.1.2 to ships of less than 90 m in length
may be accepted when a proof of longitudinal
strength has been carried out. B. Bottom Plating

new B.1 and C.1
1. Plate thickness based on load-stress criteria
1.2 The plate thicknesses are to be tapered gra-
dually, if different.
1.1 Ships with lengths L < 90 m
Gradual taper is also to be effected between the
thicknesses required for strengthening of the bottom The thickness of the bottom shell plating within 0,4 L
forward as per E.2. and the adjacent thicknesses. amidships is not to be less than:

new Section 3, B.2.1
t B1 = 1,9 ⋅ n f ⋅ a pB ⋅ k + t K [mm]
2. Definitions
Within 0,1 L forward of the aft end of the length L
k = material factor according to Section 2, B.2.
and within 0,05 L aft of F.P. the thickness is not to
pB = load on bottom [kN/m2] according to Section be less than tB2 according to 1.2.
4, B.3.

new B.1
ps, ps1= load on sides [kN/m2] according to Section
4, B.2.1
1.2 Ships with length L ≥ 90 m
pe = design pressure for the bow area [kN/m2]
according to Section 4, B.2.2 or according to The thickness of the bottom plating is not to be less
Section 4, B.2.3 for the stern area as the case than the greater of the two following values:
may be
pB
pSL = design slamming pressure [kN/m2] accord- t B1 = 18,3 ⋅ n f ⋅ a + tK [mm]
ing to Section 4, B.4. σpℓ
nf = 1,0 for transverse framing t B2 = 1, 21 ⋅ a p B ⋅ k + t K [mm]
= 0,83 for longitudinal framing
σLB = maximum bottom design hull girder bending σ pℓ = σperm 2 − 3 ⋅ τL2 − 0,89 ⋅ σ LB [N / mm 2 ]
stress [N/mm2] according to Section 5, D.1.
σLS = maximum design hull girder bending stress
new B.1
in the side shell at the station considered ac-
cording to Section 5, D.1. [N/mm2] Note
τL = maximum design shear stress due to longitu- As a first approximation σLB and τL may be taken as
dinal hull girder bending [N/mm2] according follows:
to Section 5, D.1.
12,6 L
σperm = permissible design stress [N/mm2] σLB = [N/ mm2 ] for L < 90m
k
 L  230 120
=  0,8 +  [N / mm2 ] for L < 90 m = [N/ mm2 ] for L ≥ 90m
 450  k k
230 τL = 0
= [N / mm2 ] for L ≥ 90 m
k
Chapter 1 Section 6 B Shell Structures I - Part 1
Page 6–2 GL 2012

2. Critical plate thickness, buckling strength quirements of Section 5, C.6. and Section 3, F., see
Table 3.4, load cases 1 a, 1 b, 2 and 4.
2.1 Guidance values for critical plate thickness
If this verification shows that a smaller thickness than
For ships, for which proof of longitudinal strength is that of the bottom plating is possible, such smaller
required or carried out respectively, the following thickness may be permitted.
guidance values for the critical plate thickness are
recommended:
new B.3.1

for σ LB ≤ 0,6 ⋅ ReH : 4.2 If according to Section 2, B. a higher steel

grade than A/AH is required for the bilge strake, the
tcrit = c ⋅ 2,32 ⋅ a σ LB + t K [ mm of
width ] the bilge strake is not to be less than:

b = 800 + 5 L [mm]
c = 0,5 for longitudinal framing

new B.3.2
1
= for transverse framing
2 4.3 At the end of the curved bilge strake longi-
(1 + α ) F1
tudinal stiffeners or girders are to be arranged. When
the stiffeners are arranged outside the bilge radius
α = aspect ratio a/ℓ of plate panel considered sufficient buckling resistance according to Section 3,
σLB = largest compressive stress in the bottom due F. is to be shown for the plane plate fields
to longitudinal hull girder bending  R
a L ⋅  bL +
ℓ = larger side of plate panel [m]  4 
F1 = see Section 3, F.1. (Table 3.2)
= 1,0 for longitudinal framing

2.2 Buckling strength

The guidance values obtained from 2.1 are to be
verified according to Section 3, F. Section 5, C.6.
applies where solely longitudinal hull girder bending R/6
stress need to be considered. Section 8, B.8. applies
where the combined action of longitudinal hull girder
bending and local loads has to be considered.
R

aL

3. Minimum thickness

3.1 At no point the thickness of the bottom shell

plating shall be less than: R/4 bL
a
t min = (1,5 − 0, 01 L ) L ⋅ k [mm]
taking into account the stresses according to Section
for L < 50 m 5, D.1. and the compression stresses
p ⋅ R
= L⋅k [mm] σq = [N / mm 2 ]
for L ≥ 50 m t ⋅ 103
acting coincidently in the transverse direction.
t max = 16, 0 mm in general
The thickness of these plate fields shall not be less
than the thickness derived from 1., 3. and C.1. respec-
For bulk carriers see Section 23, B.5.3, for tankers tively.
see Section 24, A.14.
For the frame spacing a and the field length ℓ, aL and

new B.2 bL + R/4 are to be taken accordingly, see sketch.
aL = spacing of the floors or transverse stiffeners
4. Bilge strake
respectively [mm]
4.1 The thickness of the bilge strake is to be bL = distance of the longitudinal stiffener from
determined as required for the bottom plating accord- the end of corner radius [mm]
ing to 1. The thickness so determined is to be verified
for sufficient buckling strength according to the re- R = bilge radius [mm]
I - Part 1 Section 6 C Shell Structures Chapter 1
GL 2012 Page 6–3

p = ps, ps1 or pB at the end of corner radius or
new C.1

pSL as the case may be [kN/m2].
1.2 Ships with lengths L ≥ 90 m
t = plate thickness [mm]
The thickness of the side shell plating is not to be less
If the derived thickness for the plane plate field is than the greater of the following values:
larger than that for the curved bilge strake according
to 4.1 the reinforcement is to be expanded by a mi- ps
nimum of R/6 into the radius. tS1 = 18,3 ⋅ n f ⋅ a + tK [mm]
σ pℓ

new B.3.3
tS2 = 1, 21 ⋅ a p ⋅ k + tK [mm]
5. Flat plate keel and garboard strake
ps1
5.1 The width of the flat plate keel is not to be tS3 = 18,3 ⋅ n f ⋅ a + tK [mm]
less than: σpℓ max

b = 800 + 5 L [mm] 2
σp ℓ = σperm − 3 ⋅ τL2 − 0,89 ⋅ σLS [N/ mm2 ]
The thickness of the flat plate keel is not to be less
than:
2
t FK = t B + 2, 0 [mm]  230  2 2
σpℓmax=  k  − 3 ⋅ τL − 0,89 ⋅ σ LS [N / mm ]
 
within 0,7 L amidships and in way
of the engine seating p = ps or pe as the case may be

= tB [mm] otherwise
new C.1

tB = thickness of the bottom plating [mm] ac- Note

cording to 1. – 3. As a first approximation σLS and τL may be taken as

new B.4.1 follows:
σ LS = 0,76 ⋅ σ LB
5.2 For ships exceeding 100 m in length, the
bottom of which is longitudinally framed, the flat 55 [ N / mm 2 ]
plate keel is to be stiffened by additional longitudinal τL =
k
stiffeners fitted at a distance of approx. 500 mm from
centre line. The sectional area of one longitudinal σLB = see B.1.2
stiffener should not be less than 0,2 L [cm2].
1.3 In way of large shear forces, the shear stres-

new B.4.2
ses are to be checked in accordance with Section 5,
D.
5.3 Where a bar keel is arranged, the adjacent
garboard strake is to have the scantlings of a flat plate
keel. 2. Minimum thickness

new B.4.3 For the minimum thickness of the side shell plating
B.3. applies accordingly.
Above a level T + co/2 above base line smaller thick-
nesses than tmin may be accepted if the stress level
C. Side Shell Plating permits such reduction.
For co see Section 4, A.2.2.
1. Plate thickness based on load-stress criteria

new C.2
1.1 Ships with lengths L < 90 m
3. Sheerstrake
The thickness of the side shell plating within 0,4 L
amidships is not to be less than: 3.1 The width of the sheerstrake is not to be less
than:
tS1 = 1,9 ⋅ n f ⋅ a ps ⋅ k + t K [mm] b = 800 + 5 L [mm]
Within 0,1 L forward of the aft end of the length L b max = 1 800 [mm]
and within 0,05 L aft of F.P. the thickness is not to
be less than tS2 according to 1.2.
new C.3.1
Chapter 1 Section 6 E Shell Structures I - Part 1
Page 6–4 GL 2012

3.2 The thickness of the sheerstrake shall, in Pfℓ = local design force [kN]
general, not be less than the greater of the following
two values: = D/100 [kN] with a minimum of 200 kN and
a maximum of 1 000 kN
t = 0,5 ( t D + t S ) [mm]
D = displacement of the ship at scantling draught [t]
= tS [mm]
Any reductions in thickness for restricted service are
tD = required thickness of strength deck not permissible.

tS = required thickness of side shell
new C.4.2

new C.3.2 5.3 In the strengthened areas the section modu-

lus of side longitudinals is not to be less than:
3.3 Where the connection of the deck stringer
with the sheerstrake is rounded, the radius is to be at W = 0,35 ⋅ Pfℓ ⋅ ℓ ⋅ k [cm3 ]
least 15 times the plate thickness ℓ = unsupported span of longitudinal [m]

new C3.3

new C.4.3
3.4 Welds on upper edge of sheerstrake are 5.4 Tween decks, transverse bulkheads, stringer
subject to special approval. and transverse walls are to be investigated for suffi-
Regarding welding between sheerstrake and deck cient buckling strength against loads acting in the
stringer see Section 7, A.2. ship's transverse direction. For scantlings of side
transverses supporting side longitudinals see Section
Holes for scuppers and other openings are to be care- 9, B.5.4.
fully rounded, any notches shall be avoided.

new C.4.4

new C.3.4

4. Buckling strength
D. Side Plating of Superstructures
For ships for which proof of longitudinal strength is
required or carried out proof of buckling strength of
the side shell is to be provided in accordance with the 1. The side plating of effective superstructures
requirements of Section 5, C.6. and Section 3, F. is to be determined according to C.

new Section 3, D.1
new Section 16, D.1

5. Strengthenings for harbour and tug ma- 2. The side plating of non-effective superstruc-
noeuvres tures is to be determined according to Section 16.

5.1 In those zones of the side shell which may 3. For the definition of effective and non-effec-
be exposed to concentrated loads due to harbour tive superstructures see Section 16, A.1. For strength-
manoeuvres the plate thickness is not to be less than ening at ends of superstructures see Section 16, A.3.
required by 5.2. These zones are mainly the plates in
way of the ship's fore and aft shoulder and in addition
amidships. The exact locations where the tugs shall
push are to be defined in the building specification. E. Strengthening of Bottom Forward
They are to be identified in the shell expansion plan.
The length of the strengthened areas shall not be less 1. Arrangement of floors and girders
than approximately 5 m. The height of the strength-
ened areas shall extend from about 0,5 m above bal- 1.1 For the purpose of arranging floors and
last draught to about 4,0 m above scantling draught. girders the following areas are defined:

Where the side shell thickness so determined exceeds x

− forward of = 0, 7 for L ≤ 100 m
the thickness required by 1. – 3. it is recommended to L
specially mark these areas. x
− forward of = (0, 6 + 0, 001 L)

new C.4.1 L
for 100 < L ≤ 150 m
5.2 The plate thickness in the strengthened areas
is to be determined by the following formula: x
− forward of = 0, 75 for L > 150 m
t = 0,65 ⋅ Pfℓ ⋅ k + t K [mm] L

new D.1.1
I - Part 1 Section 6 F Shell Structures Chapter 1
GL 2012 Page 6–5

1.2 In case of transverse framing, plate floors A = 0, 028 ⋅ pSL ⋅ a (ℓ − 0,5 ⋅ a) k [cm 2 ]
are to be fitted at every frame. Where the longitudinal
framing system or the longitudinal girder system is The area of the welded connection has to be at least
adopted the spacing of plate floors may be equal to twice this value.
three transverse frame spaces.

new D.3

new D.1.2

1.3 In case of transverse framing, the spacing of

side girders is not to exceed L/250 + 0,9 [m], up to a F. Strengthenings in Way of Propellers and
maximum of 1,4 m. Propeller Shaft Brackets, Bilge Keels
In case of longitudinal framing, the side girders are to be 1. Strengthenings in way of propellers and
fitted not more than two longitudinal frame spacings propeller shaft brackets
apart.

new D.1.3 1.1 The thickness of the shell plating in way of
propellers is to be determined according to C.
1.4 Distances deviating from those defined in 1.2
new E.1.1
and 1.3 may be accepted on the basis of direct calcula-
tions. Note

new D.1.4 It is recommended that plate fields and stiffeners of
shell structures in the vicinity of the propeller(s) be
1.5 Within the areas defined in 1.1 any scallop- specially considered from a vibration point of view
ing is to be restricted to holes for welding and for (see also Section 8, A.1.2.3 and Section 12, A.8). For
limbers. vessels with a single propeller, plate fields and stiff-

new D.1.5 eners should fulfil the following frequency criteria:

for α ≥ 0.3
x
2. Bottom plating forward of = 0, 5
L 0 < dr ≤ 1 1 < dr ≤ 2 2 < dr ≤ 3
2.1 The thickness of the bottom plating of the fplate > 4,40 ⋅ fblade 3,45 ⋅ fblade 2,40 ⋅ fblade
flat part of the ship's bottom up to a height of
0,05 · Tb or 0,3 m above base line, whichever is the fstiff > 4,40 ⋅ fblade 3,45 ⋅ fblade 2,40 ⋅ fblade
smaller value, is not to be less than:
for α < 0.3
t = 0,9 ⋅ f 2 ⋅ a pSL ⋅ k + t K [mm]
0 < dr ≤ 1 1 < dr ≤ 3
Tb = smallest design ballast draft at the forward
perpendicular [m] fplate > 3,45 ⋅ fblade 2,40 ⋅ fblade

f2 = see Section 3, A.3. fstiff > 3,45 ⋅ fblade 2,40 ⋅ fblade

new D.2
P
α =
2.2 Above 0,05 Tb or 0,3 m above base line the ∆
plate thickness may gradually be tapered to the rule P = nominal main engine output [kW]
thickness determined according to B. For ships with a
rise of floor the strengthened plating shall at least ∆ = ship's design displacement [ton]
extend to the bilge curvature. fplate 1 = lowest natural frequency of isotropic plate
field under consideration of additional

new D.2
outfitting and hydrodynamic masses [Hz]
x fstiff 1 = lowest natural frequency of stiffener
3. Stiffeners forward of = 0, 5
L under consideration of additional outfit-
ting and hydrodynamic masses [Hz]
3.1 The section modulus of transverse or longi-
tudinal stiffeners is not to be less than:

W = 0,155 ⋅ pSL ⋅ a ⋅ ℓ 2 ⋅ k [cm3 ]

new D.3
1 The natural frequencies of plate fields and stiffeners can be
3.2 The shear area of the stiffeners is not to be estimated by POSEIDON or by means of the software tool
less than: GL LocVibs which can be downloaded from the GL homepage
www.gl-group.com/en/gltools/GL-Tools.php.
Chapter 1 Section 6 H Shell Structures I - Part 1
Page 6–6 GL 2012

r 2.2 The ends of the bilge keels are to have soft

dr = ratio ≥ 1,0 transition zones according to Fig. 6.1, top. The ends
dp
of the bilge keels shall terminate above an internal
r = distance of plate field or stiffener to 12 stiffening element.
o'clock propeller blade tip position [m]
new E.2.2
dp = propeller diameter [m]
2.3 Any scallops or cut-outs in the bilge keels
fblade = propeller blade passage excitation fre- are to be avoided.
quency at n [Hz]
new E.2.3
1
= ⋅ n ⋅ z [ Hz ]
60
n = maximum propeller shaft revolution rate G. Openings in the Shell Plating
[1/min]
1. General
z = number of propeller blades

new E.1.1 Note 1.1 Where openings are cut in the shell plating
for windows or side scuttles, hawses, scuppers, sea
1.2 In way of propeller shaft brackets, Section valves etc., they are to have well rounded corners. If
19, B.4.3 has to be observed. they exceed 500 mm in width in ships up to L =
70 metres, and 700 mm in ships having a length L of

new E.1.2 more than 70 metres, the openings are to be sur-
rounded by framing, a thicker plate or a doubling.
2. Bilge keels
new F.1.1
2.1 Where bilge keels are provided they are to 1.2 Above openings in the sheer strake within
be welded to continuous flat bars, which are con- 0,4 L amidships, generally a strengthened plate or a
nected to the shell plating with their flat side by continuous doubling is to be provided compensating the
means of a continuous watertight welded seam, see omitted plate sectional area. For shell doors and similar
bottom of Fig. 6.1. large openings see J. Special strengthening is required

new E.2.1 in the range of openings at ends of superstructures.

new F.1.2
3xh
min. 100 1.3 The shell plating in way of the hawse pipes
h

is to be reinforced.

new F.1.3

2. Pipe connections at the shell plating

Scupper pipes and valves are to be connected to the
shell by weld flanges. Instead of weld flanges short
flanged sockets of adequate thickness may be used if
they are welded to the shell in an appropriate manner.
Reference is made to Section 21, D.
Construction drawings are to be submitted for approval.
t

new F.2

~ 1,5 b
H. Bow Doors and Inner Doors

1. General, definitions
r ³ 2t 1.1 Applicability
b

1.1.1 These requirements apply to the arrange-

ment, strength and securing of bow doors and inner
doors leading to a complete or long forward enclosed
superstructure.
Fig. 6.1 Soft transition zones at the ends of bilge
keels
new G.1.1.1
I - Part 1 Section 6 H Shell Structures Chapter 1
GL 2012 Page 6–7

1.1.2 Two types of bow door are covered by these
new G.1.2.4
requirements:
– Visor doors opened by rotating upwards and 1.2.5 The requirements for inner doors are based
outwards about a horizontal axis through two or on the assumption that the vehicles are effectively
more hinges located near the top of the door lashed and secured against movement in stowed posi-
and connected to the primary structure of the tion.
door by longitudinally arranged lifting arms

new G.1.2.5
– Side-opening doors opened either by rotating
outwards about a vertical axis through two or
more hinges located near the outboard edges or 1.3 Definitions
by horizontal translation by means of linking
arms arranged with pivoted attachments to the Securing device is a device used to keep the door
door and the ship. It is anticipated that side- closed by preventing it from rotating about its hinges.
opening bow doors are arranged in pairs.
Supporting device is a device used to transmit exter-
Other types of bow doors will be specially considered nal or internal loads from the door to a securing de-
in association with the applicable requirements of vice and from the securing device to the ship's struc-
these Rules. ture, or a device other than a securing device, such as

new G.1.1.2 a hinge, stopper or other fixed device, that transmits
loads from the door to the ship's structure.
1.2 Arrangement
Locking device is a device that locks a securing
1.2.1 Bow doors are to be situated above the free- device in the closed position.
board deck. A watertight recess in the freeboard deck
located forward of the collision bulkhead and above
new A.2
the deepest waterline fitted for arrangement of ramps
or other related mechanical devices, may be regarded 2. Strength criteria
as a part of the freeboard deck for the purpose of this
requirement.
2.1 Primary structure and securing and sup-

new G.1.2.1 porting devices

1.2.2 An inner door is to be provided. The inner

2.1.1 Scantlings of the primary members, securing
door is to be part of the collision bulkhead. The inner
and supporting devices of bow doors and inner doors
door needs not be fitted directly above the collision
are to be so designed that under the design loads
bulkhead below, provided it is located within the
defined in 3. the following stresses are not exceeded:
limits specified in Section 11, A.2.1 for the position
of the collision bulkhead. A vehicle ramp may be
arranged for this purpose, provided its position com- bending stress:
plies with Section 11, A.2.1. If this is not possible, a 120
separate inner weatherthight door is to be installed, as σ = [N / mm 2 ]
k
far as practicable within the limits specified for the
position of the collision bulkhead.
shear stress:

new G.1.2.2
80
τ = [N / mm 2 ]
1.2.3 Bow doors are to be so fitted as to ensure k
tightness consistent with operational conditions and
to give effective protection to inner doors. Inner equivalent stress:
doors forming part of the collision bulkhead are to be
weathertight over the full height of the cargo space 150
σv = σ 2 + 3 τ2 = [N / mm 2 ]
and arranged with fixed sealing supports on the aft k
side of the doors.

new G.1.2.3 where k is the material factor as given in Section 2,
B.2.1, but is not to be taken less than 0,72 unless a
1.2.4 Bow doors and inner doors are to be so ar- fatigue analysis is carried out according to Section 20.
ranged as to preclude the possibility of the bow door
causing structural damage to the inner door or to the
new G.2.1.1
collision bulkhead in the case of damage to or de-
tachment of the bow door. If this is not possible, a 2.1.2 The buckling strength of primary members
separate inner weathertight door is to be installed, as is to be verified according to Section 3, F.
indicated in 1.2.2.

new G.2.1.2
Chapter 1 Section 6 H Shell Structures I - Part 1
Page 6–8 GL 2012

2.1.3 For steel to steel bearings in securing and /2 /2

supporting devices, the nominal bearing pressure CL
calculated by dividing the design force by the pro-
jected bearing area is not to exceed 0,8 ⋅ ReH, where A A
ReH is the yield strength of the bearing material. For h/2
other bearing materials, the permissible bearing pres-
sure is to be determined according to the manufac- h/2
turer's specification.

new G.2.1.3 a

2.1.4 The arrangement of securing and supporting Section B - B

B
devices is to be such that threaded bolts do not carry
support forces. The maximum tension stress in way
of threads of bolts not carrying support forces is not
b
to exceed 125/k [N/mm2]. B
CL

new G.2.1.4

Section A - A
3. Design loads

Fig. 6.2 Definition angles α and β

3.1 Bow doors

3.1.1 The design external pressure to be consid- 3.1.2 The design external forces for determining
ered for the scantlings of primary members of bow scantlings of securing and supporting devices of bow
doors is not to be less than the pressure specified in doors are not to be less than:
Section 4, B.2, but is not to be taken less than:
Fx = pe ⋅ A x [ kN ]
1 + cRW
pe = 2,75⋅ ⋅ cH ( 0,22 + 0,15 ⋅ tanα)
2 Fy = pe ⋅ A y [ kN ]
2
(
⋅ 0,4 ⋅ vo ⋅ sinβ + 0,6 ⋅ L ) [kN/m2] Fz = pe ⋅ A z [ kN ]

vo = ship's speed [kn] as defined in Section 1, H.5. Ax = area [m2] of the transverse vertical projec-
tion of the door between the levels of the
L = ship's length [m], L ≤ 200 m bottom of the door and the upper deck or be-
tween the bottom of the door and the top of
cRW = service range coefficient according to the door, whichever is the lesser
Section 4, A.2.2
Ay = area [m2] of the longitudinal vertical projec-
cH = 0,0125 ⋅ L for L < 80 m tion of the door between the levels of the
bottom of the door and the upper deck or be-
= 1, 0 for L ≥ 80 m tween the bottom of the door and the top of
the door, whichever is the lesser
α = flare angle at the point to be considered,
defined as the angle between a vertical line Az = area [m2] of the horizontal projection of the
and the tangent to the side shell plating, door between the levels of the bottom of the
measured in a vertical plane normal to the door and the upper deck or between the bot-
horizontal tangent to the shell plating tom of the door and the top of the door, whi-
chever is the lesser
β = entry angle at the point to be considered,
defined as the angle between a longitudinal
line parallel to the centreline and the tangent For Ax, Ay and Az see also Fig. 6.3.
to the shell plating in a horizontal plane
h = height [m] of the door between the levels of
See also Fig. 6.2. the bottom of the door and the upper deck or
between the bottom of the door and the top

new G.3.1.1 of the door, whichever is the lesser
I - Part 1 Section 6 H Shell Structures Chapter 1
GL 2012 Page 6–9

ℓ = length [m] of the door at a height h/2 above c CL

the bottom of the door x

a
d
Fz Ax
pe = external design pressure [kN/m2] as given in
3.1.1 with angles α and β defined as follows: Fx A
y

z
elevation front view
α = flare angle measured at the point on
the bow door, ℓ/2 aft of the stem line b e
on the plane h/2 above the bottom of
the door, as shown in Fig. 6.2.
Az
CL

β = entry angle measured at the same

point as α

plan view
For bow doors, including bulwark, of unusual form or
Fig. 6.3 Bow door of visor type
proportions, e.g. ships with a rounded nose and large
stem angles, the areas and angles used for determina- 3.1.4 Moreover, the lifting arms of a visor door
tion of the design values of external forces may re- and its supports are to be dimensioned for the static
quire to be specially considered. and dynamic forces applied during the lifting and
lowering operations, and a minimum wind pressure
of 1,5 kN/m2 is to be taken into account.

new G.3.1.2

new G.3.1.4

3.2 Inner doors

3.1.3 For visor doors the closing moment M y
3.2.1 The design external pressure pe considered
under external loads is to be taken as:
for the scantlings of primary members, securing and
supporting devices and surrounding structure of inner
doors is to be taken as the greater of the following:
M y = Fx ⋅ a + 10 ⋅ W ⋅ c − Fz ⋅ b [kNm] − pe = 0, 45 ⋅ L [kN / m 2 ] or
– hydrostatic pressure ph = 10 ⋅ h [kN/m²], where
h is the distance [m] from the load point to the
W = mass of the visor door [t] top of the cargo space
where L is the ship's length, as defined in 3.1.1.
a = vertical distance [m] from visor pivot to the
new G.3.2.1
centroid of the transverse vertical projected
3.2.2 The design internal pressure pi considered
area Ax of the visor door, as shown in
for the scantlings of securing devices of inner doors
Fig. 6.3
is not to be less than:

pi = 25 [kN / m 2 ]
b = horizontal distance [m] from visor pivot to
the centroid of the horizontal projected area
new G.3.2.2
Az of the visor door, as shown in Fig. 6.3
4. Scantlings of bow doors

c = horizontal distance [m] from visor pivot to 4.1 General

the centre of gravity of visor mass, as shown
4.1.1 The strength of bow doors is to be commen-
in Fig. 6.3
surate with that of the surrounding structure.

new G.4.1.1

new G.3.1.3
Chapter 1 Section 6 H Shell Structures I - Part 1
Page 6–10 GL 2012

4.1.2 Bow doors are to be adequately stiffened and 5. Scantlings of inner doors
means are to be provided to prevent lateral or vertical
movement of the doors when closed. For visor doors 5.1 General
adequate strength for the opening and closing opera-
tions is to be provided in the connections of the lifting 5.1.1 For determining scantlings of the primary
arms to the door structure and to the ship structure members the requirements of 4.3.3 apply in conjunc-
tion with the loads specified in 3.2.

new G.4.1.2

new G.5.1.1
4.2 Plating and secondary stiffeners 5.1.2 Where inner doors also serve as vehicle
ramps, the scantlings are not to be less than those
4.2.1 The thickness of the bow door plating is not required for vehicle decks as per Section 7, B.2.
to be less than the side shell thickness tS2 according
to C.1.2, using bow door stiffener spacing, but in no
new G.5.1.2
case less than the required minimum thickness of the 5.1.3 The distribution of the forces acting on the
shell plating according to C.2. securing and supporting devices is generally to be
verified by direct calculations taking into account the

new G.4.2.1
flexibility of the structure and the actual position and
stiffness of the supports.
4.2.2 The section modulus of horizontal or vertical
stiffeners is not to be less than that required for fram-
new G.5.1.3
ing at the position of the door according to Section 9.
Consideration is to be given, where necessary, to
6. Securing and supporting of bow doors
differences in fixity between ship's frames and bow
doors stiffeners.
6.1 General

new G.4.2.2
6.1.1 Bow doors are to be fitted with adequate
means of securing and supporting so as to be com-
4.2.3 The stiffener webs are to have a net sectional
mensurate with the strength and stiffness of the sur-
area not less than:
rounding structure. The hull supporting structure in
way of the bow doors is to be suitable for the same
Q ⋅ k design loads and design stresses as the securing and
Aw = [cm 2 ]
10 supporting devices. Where packing is required, the
packing material is to be of a comparatively soft type,
Q = shear force [kN] in the stiffener calculated and the supporting forces are to be carried by the
by using uniformly distributed external de- steel structure only. Other types of packing may be
sign pressure pe as given in 3.1.1 considered. The maximum design clearance between
securing and supporting devices is generally not to

new G.4.2.3 exceed 3 mm.
A means is to be provided for mechanically fixing the
4.3 Primary structure door in the open position.

4.3.1 The bow door secondary stiffeners are to be
new G.6.1.1

supported by primary members constituting the main
stiffening of the door. 6.1.2 Only the active supporting and securing
devices having an effective stiffness in the relevant

new G.4.3.1 direction are to be included and considered to calcu-
late the reaction forces acting on the devices. Small
4.3.2 The primary members of the bow door and and/or flexible devices such as cleats intended to
the hull structure in way are to have sufficient stiff- provide load compression of the packing material are
ness to ensure integrity of the boundary support of not generally to be included in the calculations called
the door. for in 6.2.5. The number of securing and supporting
devices are generally to be the minimum practical

new G.4.3.2 whilst taking into account the redundancy require-
ments given in 6.2.6 and 6.2.7 and the available space
4.3.3 Scantlings of the primary members are gen- for adequate support in the hull structure.
erally to be verified by direct calculations in associa-
tion with the external design pressure given in 3.1.1
new G.6.1.2
and permissible stresses given in 2.1.1. Normally,
formulae for simple beam theory may be applied. 6.1.3 For opening outwards visor doors, the pivot
arrangement is generally to be such that the visor is

new G.4.3.3 self closing under external loads, that is My > 0. Mo-
I - Part 1 Section 6 H Shell Structures Chapter 1
GL 2012 Page 6–11

reover, the closing moment My as given in 3.1.3 is to
new G.6.2.5

be not less than:
6.2.6 The arrangement of securing and supporting
2
M yo = 10 ⋅ W ⋅ c + 0,1 a + b ⋅ 2
Fx2 + Fz 2
[kNm] devices in way of these securing devices is to be
designed with redundancy so that in the event of

new G.6.1.3 failure of any single securing or supporting device the
remaining devices are capable of withstanding the
6.2 Scantlings reaction forces without exceeding by more than 20
per cent the permissible stresses as given in 2.1.
6.2.1 Securing and supporting devices are to be
new G.6.2.6
adequately designed so that they can withstand the
reaction forces within the permissible stresses given 6.2.7 For visor doors, two securing devices are to
in 2.1.1. be provided at the lower part of the door, each capa-

new G.6.2.1 ble of providing the full reaction force required to
prevent opening of the door within the permissible
6.2.2 For visor doors the reaction forces applied on stresses given in 2.1.1. The opening moment Mo to
the effective securing and supporting devices assum- be balanced by this reaction force, is not to be taken
ing the door as a rigid body are determined for the less than the greater of the following values:
following combination of external loads acting simul-
taneously together with the self weight of the door: M o1 = FH ⋅ d + 5 ⋅ A x ⋅ a [kNm]
Case 1: Fx and Fz,
M o2 = ∆x ⋅ Fx2 + Fz2
Case 2: 0,7 ⋅ Fy acting on each side separately to-
gether with 0,7 ⋅ Fx and 0,7 ⋅ Fz FH = horizontal design force [kN], acting forward
The forces Fx, Fy and Fz are to be determined as in the centre of gravity, FH = 10 ⋅ W
indicated in 3.1.2 and applied at the centroid of the d = vertical distance [m] from the hinge axis to
projected areas. the centre of gravity of the door mass, as

new G.6.2.2 shown in Fig. 6.3

6.2.3 For side-opening doors the reaction forces ∆x = lever

applied on the effective securing and supporting
= 0,25 ⋅ e [m]
devices assuming the door as a rigid body are deter-
mined for the following combination of external e = distance [m] as defined in Fig. 6.3
loads acting simultaneously together with the self
weight of the door: a = distance [m] as defined in 3.1.3

Case 1: Fx, Fy and Fz acting on both doors
new G.6.2.7

Case 2: 0,7 ⋅ Fx and 0,7 ⋅ Fz acting on both doors and 6.2.8 For visor doors, the securing and supporting
devices excluding the hinges are to be capable of
0,7 ⋅ Fy acting on each door separately
resisting the vertical design force Fv = Fz – 10 ⋅ W
for Fx, Fy and Fz see 6.2.2. [kN] within the permissible stresses given in 2.1.1.

new G.6.2.3
new G.6.2.8

6.2.4 The support forces as determined according 6.2.9 All load transmitting elements in the design
to 6.2.2 and 6.2.3 shall generally result in a zero load path, from door through securing and supporting
moment about the transverse axis through the cen- devices into the ship structure, including welded
troid of the area Ax. connections, are to be of the same strength standard
as required for the securing and supporting devices.
For visor doors, longitudinal reaction forces of pin
and/or wedge supports at the door base contributing
new G.6.2.9
to this moment are not to be of the forward direction.
6.2.10 For side-opening doors, thrust bearings are

new G.6.2.4 to be provided in way of girder ends at the closing of
the two leaves to prevent one leaf to shift towards the
6.2.5 The distribution of the reaction forces acting other one under effect of unsymmetrical pressure. An
on the securing and supporting devices may require example for a thrust bearing is shown in Fig. 6.4.
to be verified by direct calculations taking into ac- Securing devices are to be provided so that each part
count the flexibility of the hull structure and the ac- of the thrust bearing can be kept secured on the other
tual position and stiffness of the supports. This is, for part. Any other arrangement serving the same pur-
instance, the case when the bow door is supported pose may be accepted.
statically undetermined.
Chapter 1 Section 6 H Shell Structures I - Part 1
Page 6–12 GL 2012

new G.6.2.10 7.2 Systems for indication/monitoring

The requirements according to 7.2.3 – 7.2.6 are only
for ships – with or without passengers – with Ro-Ro
spaces as defined in Chapter II-2, Regulation 3 of
SOLAS 74.

new G.7.2

7.2.1 Indicator lights shall be provided on the bridge

and at the operating console for indication that the bow
door and the inner door are closed and the locking and
securing devices are in their correct positions. Devia-
tions from the correct closed, locked and secured condi-
tion shall be indicated by optical and audible alarms.
The indicator panel shall be provided with
– a power failure alarm
Fig. 6.4 Thrust bearing
– an earth failure alarm
7. Arrangement of securing and locking de- – a lamp test and
vices
– separate indication for door closed, door
7.1 Systems for operation locked, door not closed and door not locked
Switching the indicating lights off is not permitted.
7.1.1 Securing devices are to be simple to operate
and easily accessible.
new G.7.2.1
Securing devices are to be equipped with mechanical 7.2.2 The indicator system is to be designed on the
locking arrangement (self locking or separate ar- self-monitoring principle and is to be alarmed by vis-
rangement), or to be of the gravity type. The opening ual and audible means if the door is not fully closed
and closing systems as well as securing and locking and not fully locked or if securing devices become
devices are to be interlocked in such a way that they open or locking devices become unsecured. The
can only operate in the proper sequence. power supply for the indicator system is to be inde-
pendent of the power supply for operating and clos-

new G.7.1.1 ing doors. The sensors of the indicator system are to
be protected from water, ice formation and mechani-
7.1.2 Bow doors and inner doors giving access to cal damages. Degree of protection: at least IP 56.
vehicle decks are to be provided with an arrangement
for remote control, from a position above the free-
new G.7.2.2
board deck of:
7.2.3 The indication panel on the navigation
– the closing and opening of the doors, and bridge is to be equipped with a selector switch "har-
bour/sea voyage", so arranged that alarm is given if
– associated securing and locking devices for vessel leaves harbour with the bow door or inner door
every door not closed and with any of the securing devices not in
Indication of the open/closed position of every secur- the correct position.
ing and locking device is to be provided at the remote
new G.7.2.3
control stations. The operating panels for operation of
doors are to be inaccessible to unauthorized persons. 7.2.4 A water leakage detection system with audi-
A notice plate, giving instructions to the effect that all ble alarm and television surveillance are to be ar-
securing devices are to be closed and locked before ranged to provide an indication to the navigation
leaving harbour, is to be placed at each operating panel bridge and to the engine control room of leakage
and is to be supplemented by warning indicator lights. through the inner door.

new G.7.1.2
new G.7.2.4

7.1.3 Where hydraulic securing devices are ap- 7.2.5 For the space between the bow door and the
plied, the system is to be mechanically lockable in inner door a television surveillance system is to be
closed position. This means that, in the event of loss fitted with a monitor on the navigation bridge and in
of the hydraulic fluid, the securing devices remain the engine control room. The system shall monitor
locked. The hydraulic system for securing and lock- the position of doors and a sufficient number of their
ing devices is to be isolated from other hydraulic securing devices. Special consideration is to be given
circuits, when in closed position. for lighting and contrasting colour of objects under
surveillance.

new G.7.1.3
I - Part 1 Section 6 J Shell Structures Chapter 1
GL 2012 Page 6–13

new G.7.2.5 1.2 For the definition of securing, supporting

and locking devices see H.1.3.
7.2.6 A drainage system is to be arranged in the
area between bow door and ramp, as well as in the
new A.2
area between the ramp and inner door where fitted.
The system is to be equipped with an acustic alarm 2. Arrangement
function to the navigation bridge for water level in
these areas exceeding 0,5 m above the car deck level. 2.1 Stern doors for passenger vessels are to be

new G.7.2.6 situated above the freeboard deck. Stern doors for
Ro-Ro cargo ships and side shell doors may be either
7.2.7 For indication and monitoring systems see below or above the freeboard deck.
also the GL Rules for Electrical Installations (I-1-3),

new H.2.1
Section 16, E.

new G.7.2.7 2.2 Side shell doors and stern doors are to be so
fitted as to ensure tightness and structural integrity
8. Operating and maintenance manual commensurate with their location and the surround-
ing structure.
8.1 An operating and maintenance manual ac-
new H.2.2
cording to IACS unified requirement S8 for the bow
door and inner door has to be provided on board and 2.3 Where the sill of any side shell door is be-
contain necessary information on: low the uppermost load line, the arrangement is to be
– description of the door system and design specially considered.
drawings

new H.2.3
– service conditions, service area restrictions and
acceptable clearances for supports In case of ice strengthening see Section 15.

– maintenance and function testing
new H.2.5

– register of inspections and repairs 2.4 Doors should preferably open outwards.
The manual has to be submitted for approval.
new H.2.4

new G.8.1
3. Strength criteria
Note
The requirements of H.2. apply.
It is recommended that inspections of the door sup-
porting and securing devices be carried out by the
new H.3
ship's staff at monthly intervals and/or following
incidents that could result in damage, including hea- 4. Design loads
vy weather and/or contact in the region of the shell
doors. These inspections are to be reported. Any 4.1 The design forces considered for the scant-
damages recorded during such inspections are to be lings of primary members, securing and supporting
reported to GL. devices of side shell doors and stern doors are to be
not less than the greater of the following values:

new G.8.1 Note

new H.4
8.2 Documented operating procedures for clos-
ing and securing the bow door and inner doors are to 4.1.1 Design forces for securing or supporting
be kept on board and posted at an appropriate place. devices of doors opening inwards:

new G.8.2 – external force: Fe = A ⋅ pe + Fp [kN]
– internal force: Fi = Fo + 10 ⋅ W [kN]

J. Side Shell Doors and Stern Doors
new H.4

4.1.2 Design forces for securing or supporting

1. General devices of doors opening outwards:

1.1 These requirements apply to side shell doors – external force: Fe = A ⋅ pe [kN]
abaft the collision bulkhead and to stern doors lead-
ing into enclosed spaces. – internal force: Fi = Fo + 10 ⋅ W + Fp [kN]

new H.1
new H.4

Chapter 1 Section 6 J Shell Structures I - Part 1
Page 6–14 GL 2012

4.1.3 Design forces for primary members: ship's angle of trim and heel which may result
in uneven loading on the hinges.
– external force: Fe = A ⋅ pe [kN]
– Shell door openings are to have well-rounded
– internal force: Fi = Fo + 10 ⋅ W [kN] corners and adequate compensation is to be
arranged with web frames at sides and
A = area of the door opening [m2] stringers or equivalent above and below.
W = mass of the door [t]
new H.5.1
Fp = total packing force [kN], where the packing
line pressure is normally not to be taken less 5.2 Plating and secondary stiffeners
than 5 N/mm The requirements of H.4.2.1 and H.4.2.2 apply ana-
Fo = the greater of Fc or 5 ⋅ A [kN] loguously with the following additions:

Fc = accidental force [kN] due to loose of cargo Where doors serve as vehicle ramps, plate thickness
and stiffener scantlings are to comply with the re-
etc., to be uniformly distributed over the a-
quirements of Section 7, B.2.
rea A and not to be taken less than 300 kN.
For small doors such as bunker doors and pi-
new H.5.2
lot doors, the value of Fc may be appropri-
ately reduced. However, the value of Fc may 5.3 Primary structure
be taken as zero, provided an additional
structure such as an inner ramp is fitted, The requirements of H.4.3 apply analoguously taking
which is capable of protecting the door from into account the design loads specified in 4.
accidental forces due to loose cargoes.

new H.5.3
pe = external design pressure determined at the
centre of gravity of the door opening and not 6. Securing and supporting of side shell and
stern doors
taken less than:
= ps acc. to Section 4, B.2.1 or: 6.1 General

pe = 10 ( T − z G ) + 25 [kN / m 2 ] The requirements of H.6.1.1 and H.6.1.2 apply ana-

logously.
for z G < T

new H.6.1
2
= 25 [kN / m ] for z G ≥ T
6.2 Scantlings
zG = height of centre of area of door above base The requirements of H.6.2.1, H.6.2.5, H.6.2.6 and
line [m] H.6.2.9 apply analogously taking into account the

new H.4 design loads specified in 4.

new H.6.2
4.2 For stern doors of ships fitted also with bow
doors, pe is not to be taken less than:
7. Arrangement of securing and locking de-
vices
 1 + cRW  2
pe = 0,6  (
 cH 0,8 + 0,6 L ) [kN/ m2 ]
 2  7.1 Systems for operation
cRW = service range coefficient as defined in
Section 4, A.2.2 7.1.1 The requirements of H.7.1.1 apply.

cH = see H.3.1.1
new H.7.1.1

new H.4 7.1.2 Doors which are located partly or totally

below the freeboard deck with a clear opening area
5. Scantlings greater than 6 m² are to be provided with an arrange-
ment for remote control, from a position above the
5.1 General freeboard deck according to H.7.1.2.

The requirements of H.4.1 apply analogously with
new H.7.1.2

the following additions:
7.1.3 The requirements of H.7.1.3 apply.
– Where doors also serve as vehicle ramps, the
design of the hinges shall take into account the
new H.7.1.3
I - Part 1 Section 6 K Shell Structures Chapter 1
GL 2012 Page 6–15

7.2 Systems for indication/monitoring their cross section effectively attached to the deck is
not to be less than:
7.2.1 The requirements of H.7.2.1, H.7.2.2 and
H.7.2.3 apply analoguously to doors leading directly W = 4 ⋅ p ⋅ e ⋅ ℓ 2 [cm3 ]
to special category spaces or Ro-Ro spaces, as de-
fined in SOLAS 1974, Chapter II-2, Reg. 3, through
which such spaces may be flooded. p = ps or pe as the case may be

new H.7.2.1 pmin = 15 kN/m2
7.2.2 For Ro-Ro passenger ships, a water leakage e = spacing of stays [m]
detection system with audible alarm and television
surveillance is to be arranged to provide an indication ℓ = length of stay [m]
to the navigation bridge and to the engine control
room of any leakage through the doors.
The dimensions for calculation of W are to be taken
For Ro-Ro cargo ships, a water leakage detection vertical to the plating starting from the base of the
system with audible alarm is to be arranged to pro- stays.
new description
vide an indication to the navigation bridge.
In addition Section 3, E.2.3 shall be considered.

new H.7.2.2

new I.4
8. Operating and maintenance manual
The requirements of H.8. apply analoguously as well
as the IACS unified requirement S9.
section for

new H.8
calculation of
the modulus

K. Bulwark

1. The thickness of bulwark plating is not to be

less than:

 L 
t =  0,75 −
1000 
L [ mm] for L ≤ 100 m

= 0,65 L [ mm] for L > 100 m
deck
L need not be taken greater than 200 m. The thick-
ness of bulwark plating forward particularly exposed
to wash of sea is to be equal to the thickness of the
forecastle side plating according to Section 16, B.1.
In way of superstructures above the freeboard deck
abaft 0,25 L from F.P. the thickness of the bulwark
plating may be reduced by 0,5 mm.
Fig. 6.5 Bulwark stay

new I.1 The stays are to be fitted above deck beams, beam
knees or carlings. It is recommended to provide flat
2. The bulwark height or height of guard rail is bars in the lower part which are to be effectively
not to be less than 1,0 m. connected to the deck plating. Particularly in ships
the strength deck of which is made of higher tensile

new I.2 steel, smooth transitions are to be provided at the end
connection of the flat bar faces to deck.
3. Plate bulwarks are to be stiffened at the
upper edge by a bulwark rail section.
new I.5

new I.3
5. On ships carrying deck cargo, the bulwark
stays are to be effectively connected to the bulwark
4. The bulwark is to be supported by bulwark and the deck. The stays are to be designed for a load
stays fitted at every alternate frame. Where the stays at an angle of heel of 30°. Under such loads the fol-
are designed as per Fig. 6.5, the section modulus of lowing stresses are not to be exceeded:
Chapter 1 Section 6 K Shell Structures I - Part 1
Page 6–16 GL 2012

L
bending stress: n = ,
40
120
σb = [N / mm 2 ]
k but need not be greater than n = 5
shear stress:
new I.7
80
τ = [N / mm 2 ] 7. Openings in the bulwarks shall have suffi-
k
cient distance from the end bulkheads of superstruc-
For loads caused by containers and by stow and lash- tures. For avoiding cracks the connection of bulwarks
ing arrangements, see also Section 21, G. to deckhouse supports is to be carefully designed.

new I.6
new I.8

6. An adequate number of expansion joints is 8. For the connection of bulwarks with the
to be provided in the bulwark. In longitudinal direc- sheer strake C.3.4 is to be observed.
tion the stays adjacent to the expansion joints shall be
as flexible as practicable.
new I.9

The number of expansion joints for ships exceeding 9. Bulwarks are to be provided with freeing
60 m in length should not be less than: ports of sufficient size. See also Section 21, D.2. and
ICLL.

new I.10
I - Part 1 Section 7 A Decks Chapter 1
GL 2012 Page 7–1

Section 7

Decks

A. Strength Deck
2. Connection between strength deck and
1. General, Definition sheerstrake

1.1 The strength deck is: 2.1 The welded connection between strength
deck and sheerstrake may be performed by fillet welds
– the uppermost continuous deck which is forming according to Section 19, Table 19.3. Where the plate
the upper flange of the hull structure thickness exceeds approximately 25 mm, a double
bevel weld connection according to Section 19, B.3.2,
– a superstructure deck which extends into 0,4 L
shall be provided for instead of fillet welds. Bevelling
amidships and the length of which exceeds
of the deck stringer to 0,65 times of its thickness in
0,15 L
way of the welded connection is admissible.
– a quarter deck or the deck of a sunk superstruc- In special cases a double bevel weld connection may also
ture which extends into 0,4 L amidships be required, where the plate thickness is less than 25 mm.

new Section 1, A.3.2
new B.2.1

1.2 In way of a superstructure deck which is to be 2.2 Where the connection of deck stringer to
considered as a strength deck, the deck below the sheerstrake is rounded, the requirements of Section 6,
superstructure deck is to have the same scantlings as a C.3.3 are to be observed.
2nd deck, and the deck below this deck the same
scantlings as a 3rd deck. The thicknesses of a strength
new B.2.2
deck plating are to be extended into the superstructure
for a distance equal to the width of the deck plating 3. Openings in the strength deck
abreast the hatchway. For strengthening of the stringer
plate in the breaks, see Section 16, A.3. 3.1 All openings in the strength deck shall have
well rounded corners. Circular openings are to be

new D.1 and D.2 edge-reinforced. The sectional area of the face bar is
not to be less than:
1.3 If the strength deck is protected by sheathing
a smaller corrosion allowance tk than required by Af = 0, 25 ⋅ d ⋅ t [cm 2 ]
Section 3, K. may be permitted. Where a sheathing
other than wood is used, attention is to be paid that the d = diameter of openings [cm]
sheathing does not affect the steel. The sheathing is to t = deck thickness [cm]
be effectively fitted to the deck..
The reinforcing face bar may be dispensed with, where

new B.1 the diameter is less than 300 mm and the smallest dis-
tance from another opening is not less than 5 × diame-
1.4 For ships with a speed v0 > 1, 6 L [kn], ter of the smaller opening. The distance between the
additional strengthening of the strength deck and the outer edge of openings for pipes etc. and the ship's side
sheerstrake may be required. is not to be less than the opening diameter.

new B.3.1.1

already covered by Section 5
3.2 The hatchway corners are to be surrounded
1.5 The following definitions apply throughout by strengthened plates which are to extend over at
this Section: least one frame spacing fore-and-aft and athwartships.
k = material factor according to Section 2, B.2. Within 0,5 L amidships, the thickness of the strength-
ened plate is to be equal to the deck thickness abreast
pD = load according to Section 4, B.1. the hatchway plus the deck thickness between the
hatchways. Outside 0,5 L amidships the thickness of
pL = load according to Section 4, C.1. the strengthened plate shall not exceed 1,6 times the
thickness of the deck plating abreast the hatchway.
tK = corrosion addition according to Section 3, K.
For ships with large hatch openings see 3.6.

new A.1
Chapter 1 Section 7 A Decks I - Part 1
Page 7–2 GL 2012

The reinforcement may be dispensed with in case of r ≥ c1 ⋅ c2

proof by a fatigue analysis.
rmin = 0,15 m for hatchway corners in the strength deck

new B.3.1.2
= 0,1 in all other locations
3.3 The hatchway corner radius is not to be less
than:  ℓ 
c1 =  fD +  ⋅ b L for hatchway corners be-
 b  750 
r = n ⋅ b 1 − 
 B  tween longitudinal deck strips and a closed
deck area, see HC1 in Fig. 7.2
rmin = 0,1 m
= 0,4 ⋅ bQ for hatchway corners between trans-
ℓ verse deck strips and a closed deck area, see
n = HC2 in Fig. 7.2
200
nmin = 0,1  ℓ  b 2L ⋅ bQ2
=  fD + for hatchway cor-
750 
⋅
nmax = 0,25  b 2L + bQ2
ℓ = length of hatchway [m] ners between two deck strips, see HC3 in Fig.
7.2
b = breadth [m], of hatchway or total breadth of
hatchways in case of more than one hatch-
HC1 HC2 HC1 HC3 HC1 HC2 HC1
way. b/B need not be taken smaller than 0,4. HC2
For ships with large hatch openings see 3.6. HC1

new B.3.1.3

3.4 Where the hatchway corners are elliptic or

parabolic, strengthening according to 3.2 is not re- Fig. 7.2 Positions of hatch corners
quired. The dimensions of the elliptical and paraboli-
cal corners shall be as shown in Fig. 7.1:
fD = coefficient for deck configuration

a L
= 0, 25 +
2 000
for hatchway corners of the strength deck and for
decks and coamings above the strength deck
L
c

= 0, 2 +
1 800
for the strength deck, decks and coamings
above the strength deck and for decks within
Fig. 7.1 Elliptic or parabolic hatch corner the distance of maximum bL below the
Where smaller values are taken for a and c, reinforced strength deck, if a further deck with the same
insert plates are required which will be considered in hatchway corner radius is arranged in a dis-
each individual case. tance of less than bL below the strength deck.

new B.3.1.4 = 0,1 for lower decks where the distance from
the strength deck exceeds bL
3.5 At the corners of the engine room casings,
strengthenings according to 3.2 may also be required, ℓ = relevant length of large deck openings [m]
depending on the position and the dimensions of the forward and/or aft of the superstructure
casing. Lmin = 100 m

new B.3.1.5
Lmax = 300 m
3.6 For ships with large deck openings according bL = breadth of deck girder alongside the hatch-
to Section 5, F. the design of the hatch corners will be way [m]
specially considered on the basis of the stresses due to
longitudinal hull girder bending, torsion and trans- bQ = breadth of cross deck strip between hatch-
verse loads. ways [m]
Approximately the following formulae can be used to For hatchway corners above or below the strength
determine the radii of the hatchway corners: deck bL and bQ are to be taken as the breadths of the
I - Part 1 Section 7 A Decks Chapter 1
GL 2012 Page 7–3

longitudinal or transverse structural members adjacent Fr.

to the hatchway corners.

b a t
M T ( z D − zo ) t
c2 = ⋅ D ⋅ 4 ki
3 ti
I y ⋅ 175 ⋅ 10 ⋅ cs

tD = plate thickness of the longitudinal structural ti a

member [mm] Lgtl.
Bhd.
ti = thickness of the hatchway corner plate [mm]
e
r b
t
1 ≥ D ≥ 0, 625
ti h

MT = total longitudinal bending moment [kNm],

according to Section 5, B.1. at the forward or c
aft edge of the relevant cross deck strip or the
relevant closed deck area
h

Iy = moment of inertia [m4] of the section accord-

ing to Section 5, A.5. in the hatchway corner
without inserted strengthened plate Fig. 7.3 Strengthening of hatchway corners

cs = according to Section 5, C.1.1 for the strength a) Opening outside of insert plate
deck c = distance of opening from butt seam

= 1,0 for the lower decks = 2 t + h + 50 [mm] for strength deck

= 2 t + h/2 + 50 [mm] for lower decks
z0 = distance of neutral axis of the hull section
from the baseline [m] b) Opening inside of insert plate
e = distance of opening from longitudinal
zD = distance of the relevant hatchway corner from bulkhead
the baseline [m]
= 2 r + h/2 [mm] for strength deck
ki = material factor according to Section 2, B. of = 1,5 r + h/2 [mm] for lower decks
the relevant hatchway corner
h = diameter of opening [mm]

new B.3.2.1 On the basis of direct calculations, other minimum
distances for specific cases may be accepted.
Where required by above calculation or on the basis of Outside 0,5 L midships the thickness of the strength-
direct fatigue assessment hatchway corners are to be ened plate shall not exceed 1,6 times the thickness of
surrounded by strengthened plates, i.e. insert plates, the deck plating abreast the hatchway.
which extend minimum distances a and b from hatch
edges (see Fig. 7.3), where
new B.3.2.3

3.7 Stresses due to lateral loads

a = 3 (ti – t) + 300 [mm]
MQ
σQ = [N / mm 2 ]
amin = 350 mm W1 ⋅ 10 3

b = r + 3 (ti – t ) + 125 [mm] MQ = bending moment around the z-axis due to the
action of the external water pressure according

new B.3.2.2 to Section 4, B.2 and/or cargo loads [kNm],
stressing the girder consisting of deck strip,
longitudinal hatch coaming and effective parts
Openings in way of hatchway corners are not to be
of longitudinal bulkhead and side shell plating
located within the following minimum distances (see
Fig. 7.3)
Chapter 1 Section 7 A Decks I - Part 1
Page 7–4 GL 2012

W1 = section modulus [m3] of the girder specified above 5.3 Deck stringer
abreast hatchway around the vertical axis. Longi-
tudinal hatch coamings can only be included, if If the thickness of the strength deck plating is less than
that of the side shell plating, a stringer plate is to be
carried sufficiently beyond the hatchway ends.
fitted having the width of the sheerstrake and the
For container ships with hatchway lengths not exceed- thickness of the side shell plating.
ing approximately 14 m and with transverse box gird-
ers of approximately equal rigidity, σQ may be deter-
new B.4.2.2
mined by the following formula:
6. Minimum thickness
 T3 
 + 0, 25 ⋅ H ⋅ p0  ℓ 2L
H  6.1 The thickness of deck plating for 0,4 L amid-
σQ =   [N / mm 2 ] ships outside line of hatchways is not to be less than
7, 2 ⋅ W1 ⋅ 103 the greater of the two following values:
p0 = see Section 4, A.2.2
t min = (4,5 + 0, 05 L) k [mm]
In the hatch corners of ships with large deck openings or
according to Section 5, F., the following equation shall
be complied with: tE = according to 7.1

σL + σQ ≤ σv L need not be taken greater than 200 m.

σv = see Section 5, D.1.2.
newB.4.3.1.1

σL = see Section 5, D.1.
6.2 When the deck is located above a level of
T + c0 above basis a smaller thickness than tmin may
4. Scantlings of strength deck of ships up to be accepted if the stress level permits such reduction.
65 m in length c0 see Section 4, A.2.2.
The scantlings of the strength deck for ships, for

new B.4.3.1.2
which proof of longitudinal strength according to
Section 5 is not required, i.e. in general for ships with
length L ≤ 65 m, the sectional area of the strength 7. Thickness at ship's ends and between
deck within 0,4 L amidships is are to be determined hatchways
such that the requirements for the minimum midship
section modulus according to Section 5, C.2. are com- 7.1 The thickness of strength deck plating tE for
plied with. 0,1 L from the ends and between hatchways is not to
The thickness within 0,4 L amidships is not to be less be less than:
than the minimum thickness according to 6. For the
ranges 0,1 L from ends the requirements of 7.1 apply. t E1 = 1, 21 ⋅ a pD ⋅ k + t K [mm]

new B.4.1 t E2 = 1,1 ⋅ a pL ⋅ k + t K [mm]

5. Scantlings of strength deck of ships of t E min = ( 5,5 + 0, 02 ⋅ L ) k [mm]

more than 65 m in length
L need not be taken greater than 200 m.
5.1 Deck sectional area
The deck sectional area abreast the hatchways, if any,
new B.4.3.2
is to be so determined that the section moduli of the
cross sections are in accordance with the requirements 7.2 Between the midship thickness and the end
of Section 5, C. thickness, the thicknesses are to be tapered gradually.

new B.4.2.1

new Section 3, B.2.1
5.2 Critical plate thickness, buckling strength
7.3 The strength of deck structure between hatch
5.2.1 The critical plate thickness is to be deter- openings has to withstand compressive transversely
mined according to Section 6, B.2. analogously. acting loads. Proof of buckling strength is to be pro-
vided according to Section 3, F.
5.2.2 In regard to buckling strength the require-
ments of Section 6, B.2.2 apply analogously.
new Section 3, D.1
I - Part 1 Section 7 B Decks Chapter 1
GL 2012 Page 7–5

B. Lower Decks f
for the range 0 < < 0,3:
F
1. Thickness of decks for cargo loads
f  f
c = 2, 00 −  5, 2 − 7, 2 
1.1 The plate thickness is not to be less than: F  F

t = 1,1 a pL ⋅ k + t K [mm] f
for the range 0,3 ≤ ≤ 1, 0:
F
t min = (5,5 + 0, 02 L) k [mm] f
c = 1, 20 − 0,517
for the 2nd deck F

= 6,0 mm for other lower decks for intermediate values of b/a the factor c is to be
obtained by direct interpolation.
L need not be taken greater than 200 m.

new C.1 f = print area of wheel or group of wheels

1.2 For the critical deck thickness see A.5.2. F = area of plate panel a ⋅ b according to Fig. 7.4

a = width of smaller side of plate panel (in gen-

2. Thickness of decks for wheel loading
eral beam spacing)
2.1 The thickness of deck plating for wheel load-
b = width of larger side of plate panel
ing is to be determined by the following formula:
F need not be taken greater than 2,5 a2
t = c⋅ P ⋅ k + tK [mm]
In case of narrowly spaced wheels these may be
P = load [kN] of one wheel or group of wheels on grouped together to one wheel print area.
a plate panel a ⋅ b considering the accelera-
tion factor av If the footprint of wheel overlaps the plate panel, the
Q load P can be scaled by: area of footprint inside plate
= (1 + a v ) panel divided by area of footprint f.
n
Q = axle load [kN]
new C.2.1
For fork lift trucks Q is generally to be taken as the
total weight of the fork lift truck. b

n = number of wheels or group of wheels per axle

av = see Section 4, C.1.1
a

= 0 for harbour conditions

c = factor according to the following formulae: f

for the aspect ratio b/a = 1:

f Fig. 7.4 Footprint of wheel
for the range 0 < < 0,3:
F
2.2 Where the wheel print area is not known, it
f  f
may approximately be determined as follows:
c = 1,87 −  3, 4 − 4, 4 F 
F  
100 ⋅ P
f f = [cm 2 ]
for the range 0,3 ≤≤ 1, 0: p
F
f
c = 1, 20 − 0, 40 p = specific wheel pressure according to Table 7.1.
F
for the aspect ratio b/a ≥ 2,5:
new C.2.1

2.3 In deck beams and girders, the stress is not to

exceed 165/k [N/mm2].

new C.2.2
Chapter 1 Section 7 C Decks I - Part 1
Page 7–6 GL 2012

Table 7.1 Specific wheel pressure tions" published by the International Chamber of
Shipping (ICS).
Specific wheel pressure p [bar]

new E.1.5
Type of vehicle Pneumatic Solid rubber
tyres tyres 2. Design loads
private cars 2 –
The design load cases (LC) which are described in 2.1
trucks 8 – - 2.3 are to be considered.
trailers 8 15

new E.1.1
fork lift trucks 6 15
As first approximation the wind loads on the helicop-
ter (WHe) or on the structure of the helicopter deck
3. Machinery decks and accommodation decks (WSt) may be determined as following values:
The scantlings of machinery decks and other accom-
modation decks have to be based on the loads given in W = 0,5 ⋅ ρ ⋅ v W2 ⋅ A ⋅ 10−3 [kN]
Section 4, C.3.
ρ = air density [kg/m3]
The thickness of the plates is not to be less than:
= 1,2 for an air temperature of 20°
t = 1,1 ⋅ a ⋅ p ⋅ k + tK [mm]
A = area exposed to wind [m2]
t min = 5 mm vW = wind velocity [m/s]

new C.3.1

new E.2.5

2.1 LC 1
C. Helicopter Decks
helicopter lashed on deck, with the following vertical
forces acting simultaneously:
1. General
– wheel and/or skid force P acting at the points
1.1 The starting/landing zone is to be dimen- resulting from the lashing position and distribu-
sioned for the largest helicopter type expected to use tion of the wheels and/or supports according to
the helicopter deck. helicopter construction.
The maximum permissible take-off weight is to be P = 0,5 ⋅ G (1 + a v ) [kN]
indicated in the drawing and will be entered in the
technical file of the Class Certificate. e
P P

new E.1.2
1.2 For scantling purposes, other loads (cargo, G = maximum permissible take-off weight [kN]
snow/ice, etc.) are to be considered simultaneously or
separately, depending on the conditions of operation av = see Section 4, C.1.1
to be expected. Where these conditions are not known, P = evenly distributed force over the contact
the data contained in 2. may be used as a basis.
area f = 30 × 30 cm for single wheel or

new E.1.3 according to data supplied by helicopter
manufacturers; for dual wheels or skids to
1.3 The following provisions in principle apply be determined individually in accordance
to starting/landing zones on special pillar-supported with given dimensions.
landing decks or on decks of superstructures and
deckhouses. e = wheel or skid distance according to heli-
copter types to be expected

new E.1.1
– force due to weight of helicopter deck Me as follows:
1.4 Requirements regarding structural fire protec-
tion see Section 22. M e (1 + a v ) [kN]

new E.1.4
– load p = 2,0 kN/m2 evenly distributed over the
Note entire landing deck for taking into account snow
or other environmental loads
For the convenience of the users of these Rules refer-
ence is made to the "Guide to Helicopter/Ship Opera-
new E.2.1
I - Part 1 Section 7 C Decks Chapter 1
GL 2012 Page 7–7

2.2 LC 2 where no data are available, vW = 25 m/s may be

helicopter lashed on deck, with the following horizon- used
tal and vertical forces acting simultaneously:
– wheel and/or skid force P acting vertically at the
new E.2.3
points resulting from the lashing position and
distribution of the wheels and/or supports ac-
cording to helicopter construction, see LC 1 3. Scantlings of structural members
P = 0,5 ⋅ G [kN]
– vertical force on supports of the deck due to 3.1 Stresses and forces in the supporting structure
weight of helicopter: are to be evaluated by means of direct calculations.

Me [kN]

new E.3.1
– load p = 2,0 kN/m2 evenly distributed over the
entire landing deck for taking into account snow
or other environmental loads 3.2 Permissible stresses for stiffeners, girders and
– horizontal forces on the lashing points of the substructure:
helicopter:
235
H = 0,6 ⋅ G + WHe [kN] σzul = [N / mm 2 ]
k ⋅ γf
WHe = wind load [kN] on the helicopter at the
lashing points
Wind velocity vW = 50 [m/s] γf = safety factor according to Table 7.2.

– horizontal force on supports of the deck due to

weight and structure of helicopter deck:
new E.3.2

H = 0,6 ⋅ Me + WSt [kN]

WSt = wind load [kN] on the structure of the Table 7.2 Safety factor γf
helicopter deck
Wind velocity vW = 50 [m/s]
γf

new E.2.2
Structural element LC 1
2.3 LC 3 LC 3
LC 2
normal landing impact, with the following forces stiffeners
acting simultaneously: 1,25 1,1
(deck beams)
– wheel and/or skid load P at two points simulta- main girders
neously, at an arbitrary (most unfavourable) 1,45 1,45
(deck girders)
point of the helicopter deck (landing zone +
safety zone) load-bearing structure
1,7 2,0
(pillar system)
P = 0, 75 G [kN]

– load p = 0,5 kN/m2 evenly distributed over the

entire landing deck for taking into account snow 3.3 The thickness of the plating is to be deter-
or other environmental loads mined according to B.2. where the coefficient c may
be reduced by 5 %.
– force due to weight of helicopter deck Me as
follows:

new E.3.3
Me [kN]

– wind load on structure in accordance with the

3.4 Proof of sufficient buckling strength is to be
wind velocity admitted for helicopter operation carried out in accordance with Section 3, F. for struc-
(vw): tures subjected to compressive stresses.
WSt [kN]

new E.3.4
I - Part 1 Section 8 A Bottom Structures Chapter 1
GL 2012 Page 8–1

Section 8

Bottom Structures

A. Single Bottom plate webs shall not be less than half the required
depth.
1. Floor plates In ships having a considerable rise of floor, the depth
of the floor plate webs at the beginning of the turn of
1.1 General bilge is not to be less than the depth of the frame.

1.1.1 Floor plates are to be fitted at every frame. The web thickness is not to be less than:
For the connection with the frames, see Section 19,
h
B.4.2. t = + 3 [mm]
100

new B.1.1.1
The web sectional area is to be determined according
1.1.2 Deep floors, particularly in the after peak, are to B.6.2.2 analogously.
to be provided with buckling stiffeners.

new B.1.2.1

new B.1.1.2
1.2.2 The face plates of the floor plates are to be
1.1.3 The floor plates are to be provided with lim-
continuous over the span ℓ. If they are interrupted at
bers to permit the water to reach the pump suctions.
the centre keelson, they are to be connected to the

new B.1.1.3 centre keelson by means of full penetration welding.

1.2 Scantlings
new B.1.2.3

1.2.1 Floor plates in the cargo hold area 1.2.3 Floor plates in the peaks

The scantlings of floor plates between afterpeak bulk- The thickness of the floor plates in the peaks is not to
head and collision bulkhead on ships without double be less than:
bottom or outside of the double bottom are to be de- t = 0,035 L + 5,0 [mm]
termined according to the following formulae.
The section modulus is not to be less than: The thickness, however, need not be greater than re-
quired by B.6.2.1.
W = c ⋅ T ⋅ e ⋅ ℓ2 [cm3 ]
The floor plate height in the fore peak above top of
keel or stem shoe is not to be less than:
e = spacing of plate floors [m]
h = 0, 06 H + 0,7 [m]
ℓ = unsupported span [m], generally measured on
upper edge of floor from side shell to side The floor plates in the afterpeak are to extend over the
shell stern tube (see also Section 13, C.1.4).
ℓmin = 0,7 B, if the floors are not supported at longi- Where propeller revolutions are exceeding 300 rpm
tudinal bulkheads (approx.), the peak floors above the propeller are to be
strengthened.
c = 7,5 for spaces which may be empty at full
draught, e.g. machinery spaces, store-rooms, Particularly in case of flat bottoms additional longitu-
etc. dinal stiffeners are to be fitted above or forward of the
propeller.
= 4,5 elsewhere
The depth of the floor plates is not to be less than:
new B.1.2.2

h = 55 ⋅ B − 45 [mm] 2. Longitudinal girders

h min = 180 mm 2.1 General

In ships having rise of floor, at 0,1 ℓ from the ends of 2.1.1 All single bottom ships are to have a centre
the length ℓ where possible, the depth of the floor girder. Where the breadth measured on top of floors
Chapter 1 Section 8 B Bottom Structures I - Part 1
Page 8–2 GL 2012

does not exceed 9 m one additional side girder is to be
Section 27, C.2.1 and C.2.2
fitted, and two side girders where the breadth exceeds
9 m. Side girders are not required where the breadth 1.2 The arrangement shall comply with Chapter
does not exceed 6 m. II-1 of SOLAS as amended. See also Section 28, D.

new B.2.1.1
Section 27, C.2.1
2.1.2 For the spacing of side girders from each
other and from the centre girder in way of bottom 1.3 Where a double bottom is required to be fitted
strengthening forward see Section 6, E.1. the inner bottom shall be continued out to the ship's
sides in such a manner as to protect the bottom to the

new B.2.1.2 turn of the bilge. Such protection will be deemed satis-
factory if the inner bottom is not lower at any part than
2.1.3 The centre and side girders are to extend as a plane parallel with the keel line and which is located
far forward and aft as practicable. They are to be con- not less than a vertical distance h measured from the
nected to the girders of a non-continuous double bot- keel line, as calculated by the formula:
tom or are to be scarphed into the double bottom by
two frame spacings. h = B/20

new B.2.1.3 However, in no case is the value of h to be less than
760 mm, and need not be taken as more than
2.2 Scantlings 2000 mm.

2.2.1 Centre girder
Section 27, C.2.3

The web thickness tw and the sectional area Af of the 1.4 Small wells for hold drainage may be ar-
face plate within 0,7 L amidships are not to be less ranged in the double bottom, their depth, however,
than: shall be as small as practicable. A well extending to
the outer bottom, may, however, be permitted at the
tw = 0, 07 L + 5,5 [mm] after end of the shaft tunnel. Other wells (e.g. for
lubricating oil under main engines) may be permitted
Af = 0, 7 L + 12 [cm 2 ]
if their arrangement does not reduce the level of pro-
tection equivalent to that afforded by a double bottom
Towards the ends the thickness of the web plate as well complying with this Section. In no case shall the verti-
as the sectional area of the top plate may be reduced cal distance from the bottom of such a well to a plane
by 10 per cent. Lightening holes are to be avoided. coinciding with the keel line be less than 500 mm.

new B.2.2.1

Section 27, C.2.4
2.2.2 Side girder Any part of a passenger ship or a cargo ship that is not
The web thickness tw and the sectional area of the face fitted with a double bottom in accordance with para-
plate Af within 0,7 L amidships are not to be less than: graphs 1.1 to 1.4 shall be capable of withstanding
bottom damages, as specified in Chapter II-1 of
tw = 0, 04 L + 5 [mm] SOLAS as amended, in that part of the ship.

Section 27, C.2.7
Af = 0, 2 L + 6 [cm 2 ]
1.5 In fore- and afterpeak a double bottom need
Towards the ends, the web thickness and the sectional not be arranged.
area of the face plate may be reduced by 10 per cent.

Section 27, C.2.2

new B.2.2.2
1.6 The centre girder should be watertight at least
for 0,5 L amidships, unless the double bottom is sub-
B. Double Bottom divided by watertight side girders. On ships which are
assigned the load line permissible for timber deck
1. General load, the double bottom is to be subdivided watertight
by the centre girder or side girders as required by the
ICLL.
1.1 On all passenger ships and cargo ships of
500 GT and more other than tankers a double bottom
Section 27, C.2.10
shall be fitted extending from the collision bulkhead to
the afterpeak bulkhead, as far as this is practicable and 1.7 For the double bottom structure of bulk carri-
compatible with the design and proper working of the ers, see Section 23, B.4.
ship. For oil tankers see Section 24.

new C.1.2
I - Part 1 Section 8 B Bottom Structures Chapter 1
GL 2012 Page 8–3

1.8 For bottom strengthening forward see Section ing to Fig. 8.1 can be used as unsupported span,
6, E. but not less than 0,8 ⋅ B.

new A.1.2
B'
1.9 For the material factor k see Section 2, B.2. a
For the corrosion allowance tK see Section 3, K. b

new A.2

1.10 For buckling strength of the double bottom B

structures see 8.3.
B' = 1 (2 B + b) for a ³ 35°
1.11 Ships touching ground whilst loading and 3
discharging B' = B for a < 35°
On request of the owner, the bottom structures of a Fig. 8.1 Fictitious breadth B'
ship which is expected to frequently touch ground
whilst loading and discharging will be examined par- In case of additional longitudinal bulkheads, the
ticularly. unsupported span can be shortened accordingly.
To fulfil this requirement, where the transverse framing
system is adopted, plate floors are to be fitted at every
new C.2.2.1
frame and the spacing of the side girders is to be re-
duced to half the spacing as required according to 3.1. 2.2.2 The thickness of the centre girder is not to be
less than:
When the longitudinal framing system is adopted, the
longitudinal girder system according to 7.5 is to be – within 0,7 L amidships:
applied.
The thickness of bottom plating is to be increased by h  h 
tm =  + 1, 0  k [mm]
10 %, compared to the plate thickness according to h a  100 
Section 6, B.1. to B.5.
for h ≤ 1200 [mm]

new C.1.3

h  h 
2. Centre girder tm =  + 3, 0  k [mm]
h a  120 
2.1 Lightening holes
for h > 1200 [mm]
Lightening holes in the centre girder are generally
permitted only outside 0,75 L amidships. Their depth – 0,15 L at the ends:
is not to exceed half the depth of the centre girder and
their lengths are not to exceed half the frame spacing. te = 0,9 ⋅ t m

new C.2.1 ha = depth of centre girder as built [mm]

tm = shall not be less than t according to 7.5
2.2 Scantlings

new C.2.2.2
2.2.1 The depth of the centre girder is not to be less
than: 3. Side girders
h = 350 + 45 ⋅ ℓ [mm] 3.1 Arrangement
h min = 600 mm At least one side girder shall be fitted in the engine
room and in way of 0,25 L aft of F.P. In the other
ℓ = unsupported span of the floor plates [m] parts of the double bottom, one side girder shall be
fitted where the horizontal distance between ship's
= B in general side and centre girder exceeds 4,5 m. Two side girders
shall be fitted where the distance exceeds 8 m, and
In case of longitudinal side bulkheads, the dis- three side girders where it exceeds 10,5 m. The dis-
tance between the bulkheads can be used as un- tance of the side girders from each other and from
supported span, but not less than 0,8 ⋅ B. centre girder and ship's side respectively shall not be
greater than:
In case of double bottoms with hopper tanks (e.g.
on bulk carriers) the fictitious breadth B' accord- 1,8 m in the engine room within the engine seatings
Chapter 1 Section 8 B Bottom Structures I - Part 1
Page 8–4 GL 2012

4,5 m where one side girder is fitted in the other 5. Double bottom tanks
parts of double bottom
5.1 Scantlings
4,0 m where two side girders are fitted in the other
parts of double bottom Structures forming boundaries of double bottom tanks
are to comply with the requirements of Section 12.
3,5 m where three side girders are fitted in the other
parts of double bottom
5.2 Fuel and lubricating oil tanks

new C.3.1
5.2.1 In double bottom tanks, fuel oil may be car-
3.2 Scantlings ried, the flash point (closed cup test) of which exceeds
60 °C.
The thickness of the side girders is not to be less than:

Section 27, C.3.3.1
h2
t = k [mm] 5.2.2 Where practicable, lubricating oil discharge
120 ⋅ h a
tanks shall be separated from the shell.
h = depth of the centre girder [mm] according to 2.2
Section 27, C.3.3.2
ha = as built depth of side girders [mm] 5.2.3 The lubricating oil circulating tanks shall be
ha need not be taken less than h to calculate t separated from the shell by at least 500 mm.

t = shall not be less than t according to 7.5
Section 27, C.3.3.3

For strengthenings under the engine seating, see C.2.3. 5.2.4 For the separation of fuel oil tanks from tanks
for other liquids, see Section 12, A.5.

new C.3.2
5.2.5 For air, overflow and sounding pipes, see
4. Inner bottom Section 21, E. as well as the GL Rules for Machinery
Installations (I-1-2), Section 11.
4.1 The thickness of the inner bottom plating is
not to be less than: 5.2.6 Manholes for access to fuel oil double bottom
tanks situated under cargo oil tanks are not permitted
t = 1,1 ⋅ a p ⋅ k + tK [mm] in cargo oil tanks or in the engine room (see also
Section 24, A.12.4).
p = design pressure [kN/m2], as applicable

new Section 27, D.1.4
= pi according to Section 4, C.2.
5.2.7 The thickness of structures is not to be less
= p1 or p2 according to Section 4, D.1. than the minimum thickness according to Section 12,
A.7.
= 10 (T – hDB)

new Section 12, H.2
The greater value is to be used.
hDB = double bottom height [m] 5.2.8 If the tank top of the lubricating oil circulat-
ing tank is not arranged at the same level as the adja-

new C.4.1 cent inner bottom, this discontinuity of the flow of
forces has to be compensated by vertical and/or hori-
4.2 If no ceiling according to Section 21, B.1. is zontal brackets.
fitted on the inner bottom, the thickness determined in The brackets shall be designed with a soft taper at the
accordance with 4.1 for p1 or p2 is to be increased by end of each arm. The thickness of the vertical brackets
2 mm. This increase is required for ships with the shall correspond to the thickness of the floor plates
notations GENERAL CARGO SHIP and MULTI- according to C.2.2, the thickness of the horizontal
PURPOSE DRY CARGO SHIP. brackets shall correspond to the tank top thickness of
the circulating tank.

new C.4.2
The brackets shall be connected to the ship structure
4.3 For strengthening in the range of grabs, see by double-bevel welds according to Section 19,
Section 23, B.4.3. B.3.2.2.

new A.1.1
new Section 12, H.1

4.4 For strengthening of inner bottom in machin- 5.3 Bilge wells

ery spaces, see C.2.4.
Bilge wells shall have a capacity of more than 0,2 m³.

new C.4.3 Small holds may have smaller bilge wells. For the use
I - Part 1 Section 8 B Bottom Structures Chapter 1
GL 2012 Page 8–5

of manhole covers or hinged covers for the access to
new C.5.1.2

the bilge suctions, see the GL Rules for Machinery
Installations (I-1-2), Section 11. Bilge wells are to be 6.1.3 Plate floors are to be fitted:
separated from the shell. Section 26, F.5. shall be – below bulkheads
applied analogously.
– below corrugated bulkheads, see also Section 3,

new Section 27, C.4.1
D.4. and Section 23, B.4.3
5.4 Sea chests
new C.5.1.3

5.4.1 The plate thickness of sea chests is not to be 6.1.4 For the remaining part of the double bottom,
less than: the spacing of plate floors shall not exceed approxi-
mately 3 m.
t = 12 ⋅ a p ⋅ k + tK [mm]
new C.5.1.4
a = spacing of stiffeners [m] 6.2 Scantlings
p = blow out pressure at the safety valve [bar]. p
is not to be less than 2 bar (see also the GL 6.2.1 The thickness of plate floors is not to be less
Rules for Machinery Installations (I-1-2), Sec- than:
tion 11)
t pf = t m − 2,0 ⋅ k [mm]

new E.1
tm = thickness of centre girder according to 2.2.2
5.4.2 The section modulus of sea chest stiffeners is
not to be less than: The thickness need not exceed 16,0 mm.

W = 56 ⋅ a ⋅ p ⋅ ℓ 2 ⋅ k [cm3 ]
new C.5.2.1

6.2.2 The web sectional area of the plate floors is

a and p see 5.4.1 not to be less than:
ℓ = unsupported span of stiffeners [m]
 2y  2
A w = ε ⋅ T ⋅ ℓ ⋅ e 1 −  k [cm ]

new E.2  ℓ 

5.4.3 The sea-water inlet openings in the shell are e = spacing of plate floors [m]
to be protected by gratings.
ℓ = span between longitudinal bulkheads, if any [m]

new E.3
= B, if longitudinal bulkheads are not fitted
5.4.4 A cathodic corrosion protection with galvanic
anodes made of zinc or aluminium is to be provided in y = distance between supporting point of the
sea chests with chest coolers. For the suitably coated plate floor (ship's side, longitudinal bulkhead)
plates a current density of 30 µA/m2 is to be provided and the section considered [m]. The distance
and for the cooling area a current density of y is not to be taken greater than 0,4 ⋅ ℓ.
180 µA/m2.
ε = 0,5 for spaces which may be empty at full

machinery rules draught, e.g. machinery spaces, store-
rooms, etc.
6. Double bottom, transverse framing system = 0,3 elsewhere
6.1 Plate floors
new C.5.2.2

6.1.1 It is recommended to fit plate floors at every 6.2.3 Where in small ships side girders are not
frame in the double bottom if transverse framing is required (see 3.1) at least one vertical stiffener is to be
adopted. fitted at every plate floor; its thickness is to be equal to
that of the floors and its depth of web at least 1/15 of

new C.5.1.1 the height of centre girder.
6.1.2 Plate floors are to be fitted at every frame:
new C.5.2.3
– in way of strengthening of the bottom forward
6.2.4 In way of strengthening of bottom forward
according to Section 6, E.
according to Section 6, E., the plate floors are to be
– in the engine room connected to the shell plating and inner bottom by
continuous fillet welding.
– under boiler seatings
Chapter 1 Section 8 B Bottom Structures I - Part 1
Page 8–6 GL 2012

new C.5.2.4 6.4.2 At the side girders, bottom frames and inner
bottom frames are to be supported by flat bars having
6.2.5 For strengthening of floors in machinery the same depth as the inner bottom frames.
spaces, see C.2.2.

new C.5.4.2

new C.5.2.5
6.5 Struts
6.3 Bracket floors
The cross sectional area of the struts is to be deter-
6.3.1 Where plate floors are not required according mined according to Section 10, C.2. analogously. The
to 6.1 bracket floors may be fitted. design force is to be taken as the following value:

new C.5.3.1 P = 0,5 ⋅ p ⋅ a ⋅ ℓ [kN]

6.3.2 Bracket floors consist of bottom frames at the p = load according to 6.3.3
shell plating and reversed frames at the inner bottom,
attached to centre girder, side girders and ship's side ℓ = unsupported span according to 6.3.3
by means of brackets.

new C.8

new C.5.3.2

6.3.3 The section modulus of bottom and inner 7. Double bottom, longitudinal framing system
bottom frames is not to be less than:
7.1 General
W = n ⋅ c ⋅ a ⋅ ℓ 2 ⋅ p ⋅ k [cm3 ] Where the longitudinal framing system changes to the
transverse framing system, structural continuity or
p = design load, as applicable, [kN/m²] as fol- sufficient scarphing is to be provided for, see also
lows: Section 3, H.
for bottom frames
new Section 3, E.1.2
p = pB according to Section 4, B.3.
7.2 Bottom and inner bottom longitudinals
for inner bottom frames
7.2.1 The scantlings are to be calculated according
p = pi according to Section 4, C.2. to Section 9, B.
= p1 or p2 according to Section 4, D.1.
new C.6.1.1
= 10 (T − h DB ) 7.2.2 Where bottom and inner bottom longitudinals
are coupled by struts in the centre of their unsupported
The greater value is to be used.
span ℓ their section moduli may be reduced to 60 % of
hDB = double bottom height [m] the values required by Section 9, B. The scantlings of
n = 0,44, if p = p2 the struts are to be determined in accordance with 6.5.

new C.6.1.2
= 0,55, if p = pi or p1
= 0,70, if p = pB 7.3 Plate floors

c = 0,60 where struts according to 6.5 are pro- 7.3.1 The floor spacing should, in general, not
vided at ℓ/2, otherwise c = 1,0 exceed 5 times the mean longitudinal frame spacing.

new C.6.2.1
ℓ = unsupported span [m] disregarding struts, if
any 7.3.2 Floors are to be fitted at every frame as de-

new C.5.3.3 fined in 6.1.3 as well as in the machinery space under
the main engine. In the remaining part of the machin-
6.4 Brackets ery space, floors are to be fitted at every alternate
frame.
6.4.1 The brackets are, in general, to be of same
new C.6.2.2
thickness as the plate floors. Their breadth is to be
0,75 of the depth of the centre girder as per 2.2. The 7.3.3 Regarding floors in way of the strengthening
brackets are to be flanged at their free edges, where of the bottom forward, Section 6, E. is to be observed.
the unsupported span of bottom frames exceeds 1 m or For ships intended for carrying heavy cargo, see
where the depth of floors exceeds 750 mm. Section 23.

new C.5.4.1
new C.6.2.3
I - Part 1 Section 8 B Bottom Structures Chapter 1
GL 2012 Page 8–7

7.3.4 The scantlings of floors are to be determined
new C.7.1.1

according to 6.2.

new C.6.2.4 Definitions

7.3.5 The plate floors should be stiffened in general pi = load on inner bottom according to Section 4,
at every longitudinal by a vertical stiffener having C.2. [kN/m2] or Section 4, C.1.3 [kN] for sin-
scantlings which fulfil the requirements in Section 9, gle loads, where applicable
B.4.
Where high density ore cargo is intended to

new C.6.2.5 be carried in the holds in a conical shape, in
agreement with GL a corresponding load dis-
7.4 Brackets
tribution pi on the inner bottom is to be used
7.4.1 Where the ship's sides are framed trans- for the calculation.
versely flanged brackets having a thickness of the
floors are to be fitted between the plate floors at every p'a = 10 T + p0 ⋅ cF [kN / m 2 ]
transverse frame, extending to the outer longitudinals (hogging condition)
at the bottom and inner bottom.

new C.6.3.1 = 10 T − p0 ⋅ cF [kN / m 2 ]
7.4.2 One bracket should be fitted at each side of (sagging condition)
the centre girder between the plate floors where the
plate floors are spaced not more than 2,5 m apart. p 0 , cF see Section 4, A.2.2
Where the floor spacing is greater, two brackets
should be fitted.
new C.7.2

new B.6.3.2 σL = design hull girder bending stress [N/mm2]

according to Section 5, D.1. (hogging or sag-
7.5 Longitudinal girder system ging, whichever condition is examined).
7.5.1 Where longitudinal girders are fitted instead σℓ = bending stress [N/mm2] in longitudinal direc-
of bottom longitudinals, the spacing of floors may be tion, due to the load p, in longitudinal girders
greater than permitted by 7.3.1, provided that adequate
strength of the structure is proved. σq = bending stress [N/mm2] in transverse direc-

new C.6.4.1 tion, due to the load p, in transverse girders

7.5.2 The plate thickness of the longitudinal girders τ = shear stress in the longitudinal girders or
is not to be less than: transverse girders due to the load p [N/mm2]

new A.2
t = (5, 0 + 0, 03 L) k [mm]

t min = 6, 0 k [mm] 8.1.2 For two or more holds arranged one behind
the other, the calculation is to be carried out for the

new C.6.4.2 hogging as well as for the sagging condition.

new C.7.1.2
7.5.3 The longitudinal girders are to be examined
for sufficient safety against buckling according to
Section 3, F. 8.2 Design loads, permissible stresses

new Section 3, D.1 8.2.1 Design loads

8. Direct calculation of bottom structures p = pi − p'a [kN / m 2 ] for loaded holds

8.1 General, Definitions = p'a [kN / m 2 ] for empty holds

8.1.1 Where deemed necessary, a direct calculation Where the grillage system of the double bottom is sub-
of bottom structures according to Section 23, B.4. may jected to single loads caused by containers, the stresses
be required. in the bottom structure are to be calculated for these
single loads as well as for the bottom load p'a as per
Where it is intended to load the cargo holds unevenly
(alternately loaded holds), this direct calculation is to 8.1.1. The permissible stresses specified therein are to
be carried out. be observed.

new C.7.2
Chapter 1 Section 8 C Bottom Structures I - Part 1
Page 8–8 GL 2012

8.2.2 Permissible stresses C. Bottom Structure in Machinery Spaces in

Way of the Main Propulsion Plant
8.2.2.1 Permissible equivalent stress σv
1. Single bottom
The equivalent stress is not to exceed the following
value: 1.1 The scantlings of floors are to be determined
according to A.1.2.1 for the greatest span measured in
230 the engine room.
σv = [N / mm 2 ]
k

new D.2.1

σv = σ x2 + σ y2 − σ x ⋅ σ y + 3 τ2 1.2 The web depth of the plate floors in way of

the engine foundation should be as large as possible.
The depth of plate floors connected to web frames
σx = stress in the ship's longitudinal direction
shall be similar to the depth of the longitudinal foun-
dation girders. In way of the crank case, the depth
= σL + σℓ shall not be less than 0,5 · h.

= 0 for webs of transverse girders The web thickness is not to be less than:

σy = stress in the ship's transverse direction h

t = + 4 [mm]
100
= σq
h = see A.1.2.1
= 0 for webs of longitudinal girders

new D.2.2

new C.7.3.1
1.3 The thickness of the longitudinal foundation
Note girders is to be determined according to 3.2.1.
new
D.2.3
Where a grillage calculation is used the following
stress definitions apply: 1.4 No centre girder needs to be fitted in way of
longitudinal foundation girders. Intercostal docking
σx = σ L + σ ℓ + 0,3 ⋅ σ q profiles are to be fitted instead. The sectional area of
the docking profiles is not to be less than:
σy = σ q + 0,3 (σ L + σ ℓ )
A w = 10 + 0, 2 L [cm 2 ]

8.2.2.2 Permissible max. values for σℓ, σq and τ Docking profiles are not required where a bar keel is
fitted. Brackets connecting the plate floors to the bar
keel are to be fitted on either side of the floors.
The stresses σℓ and τ alone are not to exceed the fol-
lowing values:
new D.2.4

150
σℓ , σq = [N / mm 2 ] 2. Double bottom
k
2.1 General
100 2
τ = [N / mm ]
k 2.1.1 Lightening holes in way of the engine foun-
dation are to be kept as small as possible with due

new C.7.3.2 regard, however, to accessibility. Where necessary,
the edges of lightening holes are to be strengthened by
means of face bars or the plate panels are to be stiff-
8.3 Buckling strength ened.
The buckling strength of the double bottom structures
new D.1.1
is to be examined according to Section 3, F. For this
purpose the design stresses according to Section 5, 2.1.2 Local strengthenings are to be provided be-
D.1. and the stresses due to local loads are to be con- side the following minimum requirements, according
sidered. to the construction, and the local.

new Section 3, D.1
new D.1.2
I - Part 1 Section 8 C Bottom Structures Chapter 1
GL 2012 Page 8–9

2.2 Plate floors 3. Engine seating

Plate floors are to be fitted at every frame. The floor 3.1 General
thickness according to B.6.2 is to be increased as
follows: 3.1.1 The following rules apply to low speed en-
gines. Seating for medium and high speed engines as
P well as for turbines will be specially considered.
3,6 + [%]
500
new D.4.1.1

minimum 5 per cent, maximum 15 per cent 3.1.2 The rigidity of the engine seating and the
surrounding bottom structure shall be adequate to keep
P = single engine output [kW] the deformations of the system due to the loads within
the permissible limits. In special cases, proof of de-
The thickness of the plate floors below web frames is formations and stresses may be required.
to be increased in addition to the above provisions. In
this case the thickness of the plate floors is not to be
new D.4.1.2
taken less than the web thickness according to Section
9, A.6.2.1. Note
If in special cases a direct calculation of motor seatings

new D.3.1 may become necessary, the following is to be observed:
– For seatings of slow speed two-stroke diesel
2.3 Side girders engines and elastically mounted medium speed
four-stroke diesel engines the total deformation
2.3.1 The thickness of side girders under an engine ∆f = fu + fo shall not be greater than:
foundation top plate inserted into the inner bottom is
to be similar to the thickness of side girders above the ∆ f = 0,2 ⋅ ℓ M [ mm ]
inner bottom according to 3.2.1.
ℓM = length of motor [m]

new D.3.2.1
fu = maximum vertical deformation of the seat-
2.3.2 Side girders with the thickness of longitudi- ing downwards within the length ℓM [mm]
nal girders according to 3.2.1 are to be fitted under the fo = maximum vertical deformation of the seat-
foundation girders in full height of the double bottom.
ing upwards within the length ℓM [mm]
Where two side girders are fitted on either side of the
engine, one may be a half-height girder under the The individual deformations fu and fo shall not
inner bottom for engines up to 3 000 kW. be greater than:

new D.3.2.2 fu max , f o max = 0,7 ⋅ ∆ f [ mm ]

2.3.3 Side girders under foundation girders are to For the calculation of the deformations the
be extended into the adjacent spaces and to be con- maximum static and wave induced dynamic in-
nected to the bottom structure. This extension abaft ternal and external differential loads due to lo-
and forward of the engine room bulkheads shall be cal loads and the longitudinal hull girder bend-
two to four frame spacings, if practicable. ing moments as well as the rigidity of the motor
are to be considered.

new D.3.2.3
– For seatings of non-elastically mounted medium
speed four-stroke diesel engines the deformation
2.3.4 No centre girder is required in way of the values shall not exceed 50 % of the above values.
engine seating (see 1.4).

new D.4.1.2 Note

new D.3.2.4
3.1.3 Due regard is to be paid, at the initial design
stage, to a good transmission of forces in transverse
2.4 Inner bottom and longitudinal direction, see also B.5.2.7.
Between the foundation girders, the thickness of the
new D.4.1.3
inner bottom plating required according to B.4.1 is to
be increased by 2 mm. The strengthened plate is to be 3.1.4 The foundation bolts for fastening the engine at
extended beyond the engine seating by three to five the seating shall be spaced no more than 3 × d apart from
frame spacings. the longitudinal foundation girder. Where the distance of
the foundation bolts from the longitudinal foundation

new D.3.3 girder is greater, proof of equivalence is to be provided.
Chapter 1 Section 8 D Bottom Structures I - Part 1
Page 8–10 GL 2012

d = diameter of the foundation bolts
new D.4.2.3

new d.4.1.4 3.2.4 The longitudinal girders of the engine seating
are to be supported transversely by means of web frames
3.1.5 In the whole speed range of main propulsion or wing bulkheads. The scantlings of web frames are to
installations for continuous service resonance vibra- be determined according to Section 9, A.6.
tions with inadmissible vibration amplitudes shall not
occur; if necessary structural variations have to be
new D.4.2.4
provided for avoiding resonance frequencies. Other-
wise, a barred speed range has to be fixed. Within a 3.2.5 Top plates are to be connected to longitudinal
range of – 10 % to + 5 % related to the rated speed and transverse girders thicker than approx. 15 mm by
no barred speed range is permitted. GL may require a means of a double bevel butt joint (K butt joint), (see
vibration analysis and, if deemed necessary, vibration also Section 19, B.3.2).
measurement.
new D.4.2.5

new D.4.1.5

3.2 Longitudinal girders

D. Transverse Thrusters
3.2.1 The thickness of the longitudinal girders
above the inner bottom is not to be less than: 1. General
In the context of this Section, transverse thrusters refer
P
t = + 6 [mm] to manoeuvring aids, which are integrated in the ship
15 structure and which are able to produce transverse
for P < 1500 kW thrust at very slow ship speeds. Retractable rudder
propellers are not transverse thrusters in the context of
P this Section.
= + 14 [mm]
750 In case of transverse thrusters which are used beyond
for 1500 ≤ P < 7500 kW that of short-term manoeuvring aids in harbours or
estuaries, e.g. Dynamic Positioning Systems (class
P notation "DP x") or use during canal passage, addi-
= + 20 [mm] tional requirements may be defined by GL.
1875

new F.1
for P ≥ 7500 kW
P = see 2.2 2. Structural principles

new D.4.2.1 2.1 Transverse thruster tunnels are to be com-
pletely integrated in the ship structure and welded to it.
3.2.2 Where two longitudinal girders are fitted on
either side of the engine, their thickness required ac- The thickness of the tunnel shall not be less than:
cording to 3.2.1 may be reduced by 4 mm.

new D.4.2.2
t min = L ⋅ k + 5 [ mm ]

new F.2.1
3.2.3 The sizes of the top plate (width and thick-
ness) shall be sufficient to attain efficient attachment
2.2 Thrust element housing structures as holding
and seating of the engine and - depending on seating
fixtures for propulsion units are to be effectively con-
height and type of engine - adequate transverse rigidity.
nected to the tunnel structure.
The thickness of the top plate shall approximately be
new F.2.2
equal to the diameter of the fitted-in bolts. The cross
sectional area of the top plate is not to be less than:
2.3 If a propulsion engine is as well directly
supported by the ship structure, it is to be ensured that
P
AT = + 30 [cm 2 ] for P ≤ 750 kW the engine housing and the supporting elements are
15 able to withstand the loading by the propulsion excita-
tion.
P
= + 70 [cm 2 ] for P > 750 kW
new F.2.3
75
2.4 All welding of structural elements which are
Where twin engines are fitted, a continuous top plate
part of the watertight integrity of the ship hull are
is to be arranged in general if the engines are coupled
generally to be carried out as welds with full root
to one propeller shaft.
penetration, as per Section 19, B., Fig. 19.8. In certain
circumstances HV- or DHV-welds with defined in-
I - Part 1 Section 8 D Bottom Structures Chapter 1
GL 2012 Page 8–11

complete root penetration as per Section 19, B., Fig. R = 3 + 0, 7 ⋅ t s ⋅ cos ( AW − 45° ) [ mm ]
19.9 may be used for lightly loaded structural ele-
ments for which the risk of damage is low.

new F.2.4 AW = angle [°] between tunnel and gear housing
support bracket
2.5 If the gear housing is supported in the vicin-
ity of the propeller hub, the support bracket shall be
ts = thickness [mm] of the gear housing support
connected to the tunnel by HV- or DHV-welds with
full root penetration. The transition shall be carried out bracket
according Fig. 8.2. and be grinded notch-free. The
radius R shall not be less than:
new F.2.5

B-B Transmission support

B B
R

Tunnel

Fig. 8.2 Connection between gear housing support bracket and thruster tunnel

3. Special designs fplate 1 = lowest natural frequency [Hz] of isotropic

plate field under consideration of additional
If suction or draining ducts are arranged in the ship's outfitting and hydrodynamic masses
bottom, the design bottom slamming pressure psl, as fstiff 1 = lowest natural frequency [Hz] of stiffener
defined in Section 4, B.4., shall be considered. under consideration of additional outfitting
and hydrodynamic masses

new F.3
fblade = propeller blade passage excitation frequency
[Hz] at n
4. Thruster grids
1
= n⋅z
For ships with ice class notation see also Section 15, 60
B.8. and for ships with class notation IW see also
Section 34, B.7. n = maximum revolution speed [1/min] of trans-
verse thruster

new F.4 z = number of propeller blades

new F.5
5. Vibration design

From a vibration point of view shell and tank struc-

tures in the vicinity of transverse thrusters should be
designed such that the following design criteria are
fulfilled:

fplate > 1,2 ⋅ fblade

1 The natural frequencies of plate fields and stiffeners can be
estimated by POSEIDON or by means of the software tool
fstiff < 0,8 ⋅ fblade or fstiff > 1,2 ⋅ fblade GL LocVibs which can be downloaded from the GL homepage
http://www.gl-group.com/en/gltools/GL-Tools.php.
Chapter 1 Section 8 E Bottom Structures I - Part 1
Page 8–12 GL 2012

E. Docking Calculation GS ⋅ C
q0 = [kN / m]
For ships exceeding 120 m in length, for ships of L KB
special design, particularly in the aft body and for
ships with a docking load of more than 700 kN/m a GS = total ship weight during docking including
special calculation of the docking forces is required. cargo, ballast and consumables [kN]
The maximum permissible cargo load to remain on- LKB = length of the keel block range [m]; i.e. in
board during docking and the load distribution are to general the length of the horizontal flat keel
be specified. The proof of sufficient strength can be
performed either by a simplified docking calculation C = weighting factor
or by a direct docking calculation. The number and
arrangement of the keel blocks shall agree with the = 1,25 in general
submitted docking plan. Direct calculations are re- = 2,0 in the following areas:
quired for ships with unusual overhangs at the ends or
with inhomogeneous distribution of cargo. – within 0,075 ⋅ LKB from both ends of the

new G.1 length LKB

Note – below the main engine

The arrangement of the keel blocks and their contact – in way of the transverse bulkheads
areas are to be defined under consideration of the ship along a distance of 2 ⋅ e
size.

new G.1 Note – in way of gas tank supports of gas tankers

e = distance of plate floors adjacent to the trans-

1. Simplified docking calculation
verse bulkheads [m]; for e no value larger
The local forces of the keel blocks acting on the bot- than 1 m needs to be taken.
tom structures can be calculated in a simplified man-
ner using the nominal keel block load q0. Based on If a longitudinal framing system is used in the double
these forces sufficient strength is to be shown for all bottom in combination with a centre line girder in
structural bottom elements which may be influenced accordance with B.2., it may be assumed that the cen-
by the keel block forces. tre line girder carries 50 % of the force and the two
adjacent (see Section 6, B.5.2) keel block longitudi-
The nominal keel block load q0 is calculated as fol- nals 25 % each.
lows, see also Fig. 8.3:

new G.2

TB = Transverse bulkhead

TB TB TB TB TB TB

Main
engine

0,075 LKB 0,075 LKB

LKB

C 2e 2e 2e 2e
e
Weighting 2,0
factor C 1,25

Fig. 8.3 Load on keel blocks

I - Part 1 Section 8 E Bottom Structures Chapter 1
GL 2012 Page 8–13

2. Direct docking calculation 3. Permissible stresses

If the docking block forces are determined by direct The permissible equivalent stress σv is:
calculation, e.g. by a finite element calculation, con-
sidering the stiffness of the ship's body and the weight R eH
σv =
distribution, the ship has to be assumed as elastically 1, 05
bedded at the keel blocks. The stiffness of the keel
blocks has to be determined including the wood layers.
new G.4
If a floating dock is used, the stiffness of the floating
dock is to be taken into consideration. 4. Buckling strength
The bottom structures are to be examined according to
Transitory docking conditions need also to be considered.
Section 3, F. For this purpose a safety factor S = 1,05

new G.3 has to be applied.

new G.5
I - Part 1 Section 9 A Framing System Chapter 1
GL 2012 Page 9–1

Section 9

Framing System

A. Transverse Framing crmin = 0,75

1. General
factor mc in new Section 3, B.3.4

s = max. height of curve
1.1 Frame spacing

new A.1
Forward of the collision bulkhead and aft of the after
peak bulkhead, the frame spacing shall in general not
exceed 600 mm. Ko

new B.1.1 Ko

1.2 Definitions
k = material factor according to Section 2, B.2.
ℓ = unsupported span [m] according to Sec-
tion 3, C., see also Fig. 9.1
Ku
ℓmin = 2,0 m
ℓKu, ℓKo = length of lower/upper bracket connec-
Ku
tion of main frames within the length ℓ
[m], see Fig. 9.1
m 2k
m = m 2k − ma2 ; m ≥
2
ma = see Section 3, A.4.
Fig. 9.1 Unsupported span of transverse frames
mk = see Section 3, C.1
e = spacing of web frames [m] 2. Main frames
p = ps or pe as the case may be
2.1 Scantlings
ps = load on ship's sides [kN/m2] according
to Section 4, B.2.1 2.1.1 The section modulus WR and shear area AR
of the main frames including end attachments are not
pe = load on bow structures [kN/m2] accord- to be less than:
ing to Section 4, B.2.2 or stern structures
according to Section 4, B.2.3 as the case WR = (1 − ma2 ) n ⋅ c ⋅ a ⋅ ℓ2 ⋅ p ⋅ cr ⋅ k [cm3]
may be
pL = 'tween deck load [kN/m2] according to upper end shear area:
Section 4, C.1.
ARO = (1 − 0,817 ⋅ ma ) 0,04 ⋅ a ⋅ ℓ ⋅ p ⋅ k [cm2 ]
p1 = pressure [kN/m2] according to Section 4,
D.1.1 lower end shear area:
p2 = pressure [kN/m2] according to Section 4,
D.1.2 ARU = (1 − 0,817 ⋅ ma ) 0,07 ⋅ a ⋅ ℓ ⋅ p ⋅ k [cm2 ]

Hu = depth up to the lowest deck [m] n = 0,9 − 0, 0035 ⋅ L for L < 100 m

new A.1
= 0,55 for L ≥ 100 m
cr = factor for curved frames

new B.2.1.1
s
= 1, 0 − 2
ℓ
Chapter 1 Section 9 A Framing System I - Part 1
Page 9–2 GL 2012

ℓ ℓ  W2 = (1 − ma2 ) ⋅ 0, 44 ⋅ c ⋅ a ⋅ ℓ 2 ⋅ p2 ⋅ cr ⋅ k [cm3 ]
c = 1, 0 −  Ku + 0, 4 ⋅ Ko 
 ℓ ℓ 
A1 = (1 − 0,817 ⋅ ma ) 0,05 ⋅ a ⋅ ℓ ⋅ p1 ⋅ k [cm2 ]
cmin = 0,6

new Section 3, B.3.3.3 A2 = (1 − 0,817 ⋅ ma ) 0,04 ⋅ a ⋅ ℓ ⋅ p2 ⋅ k [cm2 ]
Within the lower bracket connection the section
n and c see 2.1.1
modulus is not to be less than the value obtained for
c = 1,0.
new Section 12, B.3

new B.2.1.1
2.3 End attachment
2.1.2 In ships with more than 3 decks the main
frames are to extend at least to the deck above the 2.3.1 The lower bracket attachment to the bottom
lowest deck. structure is to be determined according to Section 3,
D.2. on the basis of the main frame section modulus.

new B.2.1.2

new B.2.2.1
2.1.3 The scantlings of the main frames are not to
be less than those of the 'tween deck frames above. 2.3.2 The upper bracket attachment to the deck
structure and/or to the 'tween deck frames is to be

new B.2.1.3 determined according to Section 3, D.2. on the basis
of the section modulus of the deck beams or 'tween
2.1.4 Where the scantlings of the main frames are deck frames whichever is the greater.
determined by direct strength calculations, the follow-
ing permissible stresses are to be observed:
new B.2.2.2

bending stress: 2.3.3 Where frames are supported by a longitudi-

nally framed deck, the frames fitted between web
150 frames are to be connected to the adjacent longitudi-
σb = [N / mm 2 ] nals by brackets. The scantlings of the brackets are to
k be determined in accordance with Section 3, D.2. on
the basis of the section modulus of the frames.
shear stress:

new :2.2.3
100 2
τ = [N / mm ]
k 3. 'Tween deck and superstructure frames

equivalent stress: 3.1 General

180 In ships having a speed exceeding v0 = 1, 6 ⋅ L [ kn ]

σv = σb2 + 3τ2 = [N / mm 2 ]
k the forecastle frames forward of 0,1 L from F.P. are to
have at least the same scantlings as the frames located

new B.2.1.4 between the first and the second deck.
Where further superstructures, or big deckhouses are
2.1.5 Forces due to lashing arrangements acting on arranged on the superstructures strengthening of the
frames are to be considered when determining the frames of the space below may be required.
scantlings of the frames (see also Section 21, H.).
For 'tween deck frames in tanks, the requirements for

new B.2.1.5 the section moduli W1 and W2 according to 2.2 are to
be observed.
2.1.6 For main frames in holds of bulk carriers see
new B.3.1
also Section 23, B.5.2.

new B.2.1.6 3.2 Scantlings
The section modulus Wt and shear area At of the
2.2 Frames in tanks 'tween deck and superstructure frames are not to be
less than:
The section modulus W and shear area A of frames in
tanks or in hold spaces for ballast water are not to be
Wt = 0,55 ⋅ m ⋅ a ⋅ ℓ2 ⋅ p ⋅ cr ⋅ k [cm3 ]
less than the greater of the following values:
At = (1 − 0,817 ⋅ ma ) 0,05 ⋅ a ⋅ ℓ ⋅ p ⋅ k [cm2 ]
W1 = (1 − ma2 ) n ⋅ c ⋅ a ⋅ ℓ 2 ⋅ p1 ⋅ cr ⋅ k [cm3 ]
I - Part 1 Section 9 A Framing System Chapter 1
GL 2012 Page 9–3

p = is not to be taken less than: 4.1.4 Ships not exceeding 30 m in length are to
have peak frames having the same section modulus as
2 the main frames.
b
p min = 0, 4 ⋅ p L ⋅   [kN / m 2 ]
ℓ 4.1.5 Where peaks are to be used as tanks, the
section modulus of the peak frames is not to be less
b = unsupported span of the deck beam below the than required by Section 12, B.3.1 for W2.
respective 'tween deck frame [m]
For 'tween deck frames connected at their lower ends 4.2 Frames in way of the stern
to the deck transverses, pmin is to be multiplied by the
4.2.1 The frames in way of the cruiser stern ar-
factor:
ranged at changing angles to the transverse direction
are to have a spacing not exceeding 600 mm and are to
e
f1 = 0, 75 + 0, 2 ≥ 1, 0 extend up to the deck above peak tank top maintaining
a the scantlings of the peak frames.

new B.3.2 4.2.2 An additional stringer may be required in the
aft body outside the after peak where frames are in-
3.3 End attachment clined considerably and not fitted vertically to the
shell.
'Tween deck and superstructure frames are to be con-
nected to the main frames below, or to the deck. The
new B.4.2
end attachment may be carried out in accordance with
Fig. 9.2. 5. Strengthenings in fore- and aft body
For 'tween deck and superstructure frames 2.3.3 is to
be observed, where applicable. 5.1 General

new B.3.3 In the fore body, i.e. from the forward end to 0,15 L
behind F.P., flanged brackets have to be used in prin-
ciple.
As far as practicable and possible, tiers of beams or
web frames and stringers are to be fitted in the fore-
and after peak.

new B.5.1

Fig. 9.2 Typical end attachments of 'tween deck 5.2 Tiers of beams
and superstructure frames
5.2.1 Forward of the collision bulkhead, tiers of
4. Peak frames and frames in way of the beams (beams at every other frame) generally spaced
stern no more than 2,6 m apart, measured vertically, are to
be arranged below the lowest deck within the fore-
peak. Stringer plates are to be fitted on the tiers of
4.1 Peak frames
beams which are to be connected by continuous weld-
ing to the shell plating and by a bracket to each frame.
4.1.1 Section modulus WP and shear area AP of the
The scantlings of the stringer plates are to be deter-
peak frames are not to be less than: mined from the following formulae:
Wp = 0,55 ⋅ m ⋅ a ⋅ ℓ2 ⋅ p ⋅ cr ⋅ k [cm3 ] width: b = 75 L [mm]

Ap = (1 − 0,817 ⋅ ma ) 0,05 ⋅ a ⋅ ℓ ⋅ p ⋅ k [cm2 ] L

thickness: t = 6, 0 + [mm]
40

new B.4.1.1

new B.5.2.1
4.1.2 Where the length of the forepeak does not
exceed 0,06 L the section modulus required at half 5.2.2 The cross sectional area of each beam is to be
forepeak length may be maintained throughout the determined according to Section 10, C.2. for a load
entire forepeak.
P = A ⋅ p [kN]
4.1.3 The peak frames are to be connected to the
stringer plates to ensure sufficient transmission of A = load area of a beam [m2]
shear forces.
new B.5.2.2

new B.4.1.2
Chapter 1 Section 9 A Framing System I - Part 1
Page 9–4 GL 2012

5.2.3 In the after peak, tiers of beams with stringer 5.3.2 Vertical transverses are to be interconnected
plates generally spaced 2,6 m apart, measured verti- by cross ties the cross sectional area of which is to be
cally, are to be arranged as required under 5.2.1, as far determined according to 5.2.2.
as practicable with regard to the ship's shape.

new B.5.3.2

new B.5.2.3
5.3.3 Where web frames and stringers in the fore
5.2.4 Intermittent welding at the stringers in the body are dimensioned by strength calculations the
after peak is to be avoided. Any scalloping at the shell stresses shall not exceed the permissible stresses in
plating is to be restricted to holes required for welding 2.1.4.
and for limbers.

new B.5.3.3

new B.5.2.4
Note
5.2.5 Where peaks are used as tanks, stringer plates
are to be flanged or face bars are to be fitted at their Where a large and long bulbous bow is arranged a
inner edges. Stringers are to be effectively fitted to the dynamic pressure psdyn is to be applied unilaterally.
collision bulkhead so that the forces can be properly The unilateral pressure can be calculated approxi-
transmitted. mately as follows:

new B.5.2.5  z
p sdyn po ⋅ cF ⋅  1 + [ kN / m 2 ]
T 
=

5.2.6 Where perforated decks are fitted instead of
tiers of beams, their scantlings are to be determined as po, cF, z and f according to Section 4, with f = 0,75.
for wash bulkheads according to Section 12, G. The
requirements regarding cross sectional area stipulated For the effective area of psdyn, the projected area of
in 5.2.2 are, however, to be complied with. the z-x-plane from forward to the collision bulkhead
may be assumed.

new B.5.2.6

new B.5.3.3 Note
5.3 Web frames and stringers
5.4 Web frames and stringers in 'tween decks
5.3.1 Where web frames and supporting stringers and superstructure decks
are fitted instead of tiers of beams, their scantlings are
to be determined as follows: Where the speed of the ship exceeds v0 = 1,6 ⋅ L [kn]
or in ships with a considerable bow flare respectively,
– Section modulus: stringers and transverses according to 5.3 are to be
fitted within 0,1 L from forward perpendicular in
W = 0,55 ⋅ e ⋅ ℓ 2 ⋅ p ⋅ n c ⋅ k [cm3 ] 'tween deck spaces and superstructures.
– Web shear area at the supports: The spacing of the stringers and transverses shall be
less than 2,8 m. A considerable bow flare exists, if the
A w = 0, 05 ⋅ e ⋅ ℓ1 ⋅ p ⋅ k [cm2 ] flare angel exceeds 40°, measured in the ship's trans-
verse direction and related to the vertical plane.
ℓ = unsupported span [m], without considera-
tion of cross ties, if any
new B.5.4

ℓ1 = similar to ℓ, however, considering cross 5.5 Tripping brackets

ties, if any
5.5.1 Between the point of greatest breadth of the
nc = coefficient according to the following ship at maximum draft and the collision bulkhead
Table 9.1 tripping brackets spaced not more than 2,6 m, meas-

new B.5.3.1 ured vertically, according to Fig. 9.3 are to be fitted.
The thickness of the brackets is to be determined ac-
cording to 5.2.1. Where proof of safety against trip-
Table 9.1 Reduction coefficient nc ping is provided tripping brackets may partly or com-
pletely be dispensed with.
Number of cross ties nc
new B.5.5.1

0 1,0
1 0,5
3 0,3
≥3 0,2
I - Part 1 Section 9 B Framing System Chapter 1
GL 2012 Page 9–5

6.2 Scantlings
6.2.1 The section modulus of web frames is not to
be less than:

W = 0,8 ⋅ e ⋅ ℓ 2 ⋅ ps ⋅ k [cm3 ]
The moment of inertia of web frames is not to be less
than:

I = H (4,5 H − 3,5) ci ⋅ 102 [cm 4 ]

for 3 m ≤ H ≤ 10 m

Fig. 9.3 Tripping brackets I = H (7,25 H − 31) ci ⋅ 102 [cm 4 ]

5.5.2 In the same range, in 'tween deck spaces and for H > 10 m
superstructures of 3 m and more in height, tripping
brackets according to 5.5.1 are to be fitted. ci = 1 + (Hu – 4) 0,07

new B.5.5.2 The scantlings of the webs are to be calculated as

follows:
5.5.3 Where peaks or other spaces forward of the depth : h = 50 ⋅ H [mm],
collision bulkhead are intended to be used as tanks,
tripping brackets according to 5.5.1 are to be fitted h min = 250 mm
between tiers of beams or stringers.
h

new B.5.5.3 thickness : t = [mm],
32 + 0, 03 ⋅ h
5.5.4 For ice strengthening, see Section 15. t min = 8, 0 mm

new B.5.5.4
new B.6.2.1
6.2.2 Ships with a depth of less than 3 m are to have
6. Web frames in machinery spaces web frames with web scantlings not less than 250 ×
8 mm and a minimum face sectional area of 12 cm2.
6.1 Arrangement

new B.6.2.1
6.1.1 In the engine and boiler room, web frames
6.2.3 In very wide engine rooms it is recommended
are to be fitted. Generally, they should extend up to
to provide side longitudinal bulkheads.
the uppermost continuous deck. They are to be spaced
not more than 5 times the frame spacing in the engine
new B.6.2.2
room.

new B.6.1.1
B. Bottom-, Side- and Deck Longitudinals,
6.1.2 For combustion engines, web frames shall Side Transverses
generally be fitted at the forward and aft ends of the
engine. The web frames are to be evenly distributed 1. General
along the length of the engine.
1.1 Longitudinals shall preferably be continuous

new B.6.1.2 through floor plates and transverses.

6.1.3 Where combustion engines are fitted aft, For longitudinal frames and beams sufficient fatigue
stringers spaced 2,6 m apart are to be fitted in the strength according to Section 20 is to be demonstrated.
engine room, in alignment with the stringers in the Ahead of 0,1 L from F.P. webs of longitudinals are to
after peak, if any. Otherwise the main frames are to be be connected effectively at both sides. If the flare
adequately strengthened. The scantlings of the string- angle is more than 40° additional heel stiffeners or
ers shall be similar to those of the web frames. At least brackets are to be arranged.
one stringer is required where the depth up to the
lowest deck is less than 4 m.
new C.1.1

new B.6.1.3 1.2 Where longitudinals abut at transverse bulk-

heads or webs, brackets are to be fitted. These longi-
6.1.4 For the bottom structure in machinery spaces, tudinals are to be attached to the transverse webs or
see Section 8, C. bulkheads by brackets with the thickness of the stif-
Chapter 1 Section 9 B Framing System I - Part 1
Page 9–6 GL 2012

feners web thickness, and with a length of weld at the = pi according to Section 4, C.2. for inner
longitudinals equal to 2 × depth of the longitudinals. bottom longitudinals, however, not less

new C.1.2 than the load corresponding to the dis-
tance between inner bottom and deepest
1.3 Outside the upper and the lower hull flange, load waterline
the cross sectional areas stipulated in 1.2 may be re-
= pL according to Section 4, C.1. for longitu-
duced by 20 per cent.(
dinals of cargo decks and for inner bot-
1.4 Where longitudinals are sniped at watertight tom longitudinals
floors and bulkheads, they are to be attached to the
new C.2
floors by brackets of the thickness of plate floors, and
with a length of weld at the longitudinals equal to 2 × p0 = according to Section 4, A.2.2
depth of the bottom longitudinals. (For longitudinal cF = according to Section 4, Table 4.1
framing systems in double bottoms, see Section 8, B.7.)

new C.1.3 Tmin = smallest ballast draught
σL = axial stress in the profile considered [N/mm2]
1.5 For a strength of longitudinals see Section 3,
according to Section 5, D.1.
F.2.3 and 3.
z = distance of structure [m] above base line

new Section 3, D.1

new A.1
2. Definitions xℓ = distance [mm] from transverse structure at I
and J respectively (see Fig. 9.4)
ℓ = unsupported span [m], see also Fig. 9.4.

new Section 3, B.3.8.1

new A.1
p = load [kN/m2] 3. Scantlings of longitudinals and longitudi-
nal beams
= pB according to Section 4, B.3. for bottom
longitudinals 3.1 Section modulus Wℓ and shear area Aℓ of
= ps or pe according to Section 4, B.2. for longitudinals and longitudinal beams of the strength
side longitudinals deck are not to be less than:

= p1 according to Section 4, D.1.1, for longi- 83

Wℓ = m ⋅ a ⋅ ℓ2 ⋅ p [cm3 ]
tudinals at decks and at ship's sides, at σ pr
longitudinal bulkheads and inner bottom
in way of tanks Aℓ = (1 − 0,817 ⋅ ma ) 0, 05 ⋅ a ⋅ ℓ ⋅ p ⋅ k [cm 2 ]

For bottom longitudinals p due to tank pres- The permissible stress σpr is to be determined accord-
sure need not to be taken larger than: ing to the following formulae:

p1 − (10 ⋅ Tmin − p0 ⋅ cF ) [kN/m 2 ] σpr = σperm − σL [N / mm2 ]

For side longitudinals below Tmin p need not 150

σpr ≤ [N / mm2 ]
to be taken larger than: k
  L  230
z  2 σperm =  0,8 +  [N / mm2 ]
p1 − 10 ( Tmin − z ) + p0 ⋅ cF 1 +  [kN/m ]  450  k
 Tmin 
230
with p ≤ p1 σperm max = [N / mm2 ]
k

= pd according to Section 4, D.2. for longitu-
new C.3.2

dinals at ship's sides, at longitudinal For side longitudinals Wℓ and Aℓ shall not be less than:
bulkheads in tanks intended to be par-
tially filled 83
Wℓ min = m ⋅ a ⋅ ℓ 2 ⋅ ps1 [cm3 ]
= pD according to Section 4, B.1. for deck σpermmax − σL
longitudinals of the strength deck
Aℓ min = (1− 0,817 ⋅ ma ) 0,037 ⋅ a ⋅ ℓ ⋅ ps1 ⋅ k [cm2 ]
= pDA according to Section 4, B.5. for exposed
decks which are not to be treated as
new C.3.3
strength deck
I - Part 1 Section 9 B Framing System Chapter 1
GL 2012 Page 9–7

ps1 according to Section 4, B.2.1.1 and 2.1.2 respec-
new C.3.4

tively.
3.3 Where the scantlings of longitudinals are

new A.1 determined by strength calculations, the total stress
For fatigue strength calculations according to Section comprising local bending and normal stresses due to
20, Table 20.1 bending stresses due to local stiffener longitudinal hull girder bending is not to exceed the
bending and longitudinal normal stresses due to global total stress value σperm and σperm max respectively as
hull girder bending are to be combined. Bending defined in 3.1.
stresses from local stiffener bending due to lateral

new C.3.5
loads p can be calculated as follows:
for 0 ≤ xℓ ≤ ℓK 3.4 If nonsymmetrical sections are used additional
stresses according to Section 3, L. shall be considered.
83 ⋅ m ⋅ a ⋅ ℓ 2 ⋅ p
new C.3.6
σA = + σh [N/mm2]
Wa
3.5 Where necessary, for longitudinals between
for xℓ = hs + ℓb transverse bulkheads and side transverses additional
stresses resulting from the deformation of the side
σB = σA ⋅ m1 [N/mm2] transverses are to be taken into account.

Wa = section modulus of the profile [cm3] includ- If no special verification of stresses due to web frame
deformations is carried out, the following minimum
ing effective plate width according to Section
values are to be considered for fatigue strength verifi-
3, F.2.2
cation of side longitudinals:
σh according to Section 3, L.1. 2
hw  ℓR 
σDF = ± 0,1 ⋅  Cp (1 − Cp )  [N / mm 2 ]
m1 = 1 – 4 ⋅ c3 ⋅ [1 – 0,75 ⋅ c3] ℓ − ∑ ℓ b  DF 

for position B at I hw = web height of profile i [mm] (see Section 3,

Fig. 3.3)
h sI + ℓ bI − ℓ KI
c3I =
103 ⋅ ℓ ⋅ m K Σℓb = (hsI + ℓbI + hsJ + ℓbJ) ⋅ 10–3 [m] (see Section 3,
Fig. 3.1)
for position B at J
ℓR = unsupported web frame length [m] (see Fig. 9.4)
h sJ + ℓ bJ − ℓ KJ DF = height of web frame [m] (see Fig. 9.4)
c3J =
103 ⋅ ℓ ⋅ m K
Cp = weighting factor regarding location of the profile:
The stresses at point A shall not be less than the
(z − z Ro ) / ℓ R + CT
stresses in adjacent fields (aft of frame I and forward =
of frame J respectively). 1 + 2 ⋅ CT

new C.3.7 zRo = z-coordinate of web frame outset above basis

[m] (see Fig. 9.4), zRo < T
In way of curved shell plates (e.g. in the bilge area)
section modulus Wℓmin, shear area Aℓmin, and stress CT = correction regarding location of the profile i
σB can be reduced by the factor CR. to the water line

1 z
= 1,1 − 0 ≤ CT ≤ 0,1
CR = 4 T
a ⋅ℓ ⋅t
1+
new C.3.8
0, 006 ⋅ Ia ⋅ R 2

t = thickness of shell plating [mm] Fig. 9.4 Definitions

Ia = moment of inertia of the longitudinal frame 3.6 Where struts are fitted between bottom and
[cm4], including effective breadth inner bottom longitudinals, see Section 8, B.7.2.
R = bending radius of the plate [m] 3.7 For scantlings of side longitudinals in way of

new C.3.3 those areas which are to be strengthened against loads
due to harbour and tug manoeuvres see Section 6, C.5.
3.2 In tanks, the section modulus is not to be less
new C.3.1
than W2 according to Section 12, B.3.1.1.
Chapter 1 Section 9 B Framing System I - Part 1
Page 9–8 GL 2012

3.8 In the fore body where the flare angle α is and attached heel stiffener are to be designed within the
more than 40° and in the aft body where the flare limit of the permissible stresses acc. 4.7. At intersections
angle α is more than 75° the unsupported span of the of longitudinals with transverse tank boundaries the
longitudinals located above Tmin – c0 shall not be local bending of tank plating shall be prevented by effec-
larger than 2,6 m. Otherwise tripping brackets accord- tive stiffening.
ing to A.5.5 are to be arranged. c0 see Section 4, A.2.
new C.4.1

new C.3.9
4.2 The total force P transmitted from the longi-
3.9 The side shell longitudinals within the range tudinal to the transverse support member is given by:
from 0,5 m below the minimum draught up to 2,0 m
above the maximum draught and a waterline breadth P = (1 − 0,817 ⋅ m a ) ⋅ a ⋅ ℓ ⋅ p [kN]
exceeding 0,9 ⋅ B are to be examined for sufficient
strength against berthing impacts. The force induced p = design load [kN/m2] for the longitudinal acc.
by a fender into the side shell may be determined by: to 2.

0 < D ≤ 2 100 [t]: Pf = 0,08 · D [kN] ma = see A.1.2

2 100 < D ≤ 17 000 [t]: Pf = 170 [kN] In case of different conditions at both sides of the
transverse support member the average unsupported
D > 17 000 [t]: Pf = D/100 [kN] length ℓ and the average load p are to be used.
D = displacement of the ship at scantling draught [t]
new C.4.2
Dmax = 100 000 t
4.3 The stiffness of the connections between the

new C.3.10 longitudinal and transverse support member are ac-
counted for by considering Sh, Ss and Sc. If no heel
3.10 In order to withstand the load Pf the section stiffener or collar plate are fitted, the respective values
modulus Wℓ of side shell longitudinals are not to be are to be taken as (Sh, Sc) = 0.
less than:
heel stiffener:
k ⋅ Mf
Wℓ = ⋅ 103 [cm3 ]
235  450 
E ⋅ ℓ h ⋅ t h ⋅ 1 + 
 ℓh 
k = material factor Sh = [N/mm]
380
Mf = bending moment
web:
P
= f ( ℓ − 0,5 ) [kNm] Ss =
G ⋅ hs ⋅ ts [N/mm]
16 bs
ℓ = unsupported length [m]
collar plate:

new C.3.11
G ⋅ hc ⋅ tc [N/mm]
Sc =
bc
4. Connections between transverse support
member and intersecting longitudinal
G = shear modulus [N/mm2]
4.1 At the intersection of a longitudinal with a trans-
verse support member (e.g., web), the shear connections ℓhc = connection length [mm] of heel stiffener
I - Part 1 Section 9 B Framing System Chapter 1
GL 2012 Page 9–9

Heel stiffener
Web frame

(th)

bs lh
(ts)

lhc
hs
Side longitudinal

Web frame Heel stiffener

bs bc lh
(ts)

lhc
Lug lk
plate
hc (tc)
hs Side longitudinal

Fig. 9.5 Typical intersections of longitudinals and transverse support members

ℓh = length [mm] of the minimum heel stiffener

cross-sectional area; 4.4 The force Ph transmitted from the longitudi-
nal to the transverse member by the heel stiffener is to
th, bs, hs, ts, bc, hc, tc [mm] see Fig. 9.5 be taken as follows:
ℓk see 2.

new C.4.3 Ph = ε h ⋅ P [kN]

Chapter 1 Section 9 B Framing System I - Part 1
Page 9–10 GL 2012

Sh τp = permissible shear stress in the fillet weld acc.

εh =
Sh + Ss + Sc to Section 19, Table 9.2

new C.4.4 i = s for the shear connection of longitudinal and

transverse support member
4.5 The forces Ps and Pc transmitted through the = c for the shear connection of longitudinal and
shear connections to the transverse support member collar plate
are to be taken as follows:

new C.4.7
Ps = εs ⋅ P [kN]
Ss 4.8 The cross-sectional area of a collar plate is to
with εs = be such that the calculated bending stress does not
Sh + Ss + Sc exceed the permissible stresses.

Pc = εc ⋅ P [kN] – bending stress of collar plate

Sc
with εc = 3 ⋅103 ⋅ Pc ⋅ bc 150
Sh + Ss + Sc σc = ≤ [N/mm2]
h c2 ⋅ t c k

new C.4.5
4.6 The cross-sectional areas of a heel stiffener – bending stress in the fillet weld connection of
are to be such that the calculated stresses do not ex- the collar plate
ceed the permissible stresses.
1,5 ⋅ 103 ⋅ Pc ⋅ b c
– normal stress at minimum heel stiffener cross- σ weld,c = ≤ σ vp [N/mm2]
sectional area: h c2 ⋅ a

new C.4.8
103 ⋅ Ph 150
σaxial = ≤ [N/mm2]
ℓh ⋅ th k 4.9 For typical heel stiffeners (Fig. 9.5, upper
part) at outer shell the fatigue strength shall be ap-
– normal stress in the fillet weld connection of proximated by a simplified approach.
heel stiffener:

new C.4.9
3
10 ⋅ Ph
σweld = ≤ σvp [N/mm2] 4.9.1 The fatigue relevant pressure range ∆p in-
2 ⋅ a ⋅ ( ℓ hc + t h + a )
duced by tank pressure and outer pressure on the shell
or a superposition of both is given by the pressure
a = throat thickness [mm] of fillet weld, see Sec- difference between maximum and minimum load
tion 19, B.3.3 according to Section 20, Table 20.1.
σvp = permissible equivalent stress in the fillet weld
acc. to Section 19, Table19.2
new C.4.9.1

new C.4.6 4.9.2 The permissible fatigue stress range is given by

4.7 The cross-sectional areas of the shear connec- 90 ⋅ f n ⋅ f r

∆σ p = [N/mm2]
tions are to be such that the calculated stresses do not  ℓh  2
exceed the permissible stresses.  50 + C  ⋅ k sp
 
– shear stress in the shear connections to the
transverse support member: fr = mean stress factor as given in Section 20

fn = factor as given in Section 20, Table 20.2 for

103 ⋅ Pi 100
τi = ≤ [N/mm2] welded joints
hi ⋅ ti k
C = 1 with collar plate; without C = 2
– shear stress in the shear connections in way of
fillet welds: ksp = factor for additional stresses in non-symme-
trical longitudinal sections according to Sec-
103 ⋅ Pi tion 3, Table 3.7
τ weld,i = ≤ τp [N/mm2]
2 ⋅ a ⋅ hi
new C.4.9.2
I - Part 1 Section 9 B Framing System Chapter 1
GL 2012 Page 9–11

4.9.3 A comprehensive fatigue strength analysis In the fore body where flare angles α are larger than
according to Section 20, C. may substitute the simpli- 40° the web in way of the deck beam has to be stiff-
fied approach for the typical heel stiffener and is re- ened.
quested if more complex designs with soft heel and/or
toe or additional brackets are necessary.

new C.5.2

new C.4.9.3

5. Side transverses 5.3 In tanks the web thickness shall not be less
than the minimum thickness according to Section 12,
5.1 Section modulus W and shear area AW of A.7., and the section modulus and the cross sectional
area are not to be less than W2 and Aw2 according to
side transverses supporting side longitudinals are not
Section 12, B.3.
to be less than:

W = 0,55 ⋅ e ⋅ ℓ 2 ⋅ p ⋅ k [cm3 ]
new C.5.3

A W = 0, 05 ⋅ e ⋅ ℓ ⋅ p ⋅ k [cm 2 ] 5.4 The webs of side transverses within the range

from 0,5 m below the minimum draught up to 2,0 m

new C.5.1 above the maximum draught and a waterline breadth
exceeding 0,9 ⋅ B are to be examined for sufficient
5.2 Where the side transverses are designed on buckling strength against berthing impacts. The force
the basis of strength calculations the following stresses induced by a fender into the web frame may be deter-
are not to be exceeded: mined as in 3.9.

150
σb = [N / mm 2 ]
new C.5.4
k

100
τ = [N / mm 2 ] 5.5 In order to withstand the load Pf on the web
k frames, the following condition has to be met:
180
σv = σ2b + 3τ2 ≤ [N / mm 2 ]
k Pf ≤ Pfu

new C.5.2
Side transverses and their supports (e. g. decks) are to Pf see 3.9
be checked according to Section 3, F. with regard to
their buckling strength.
Pfu = t s2 ⋅ R eH [C + 0,17] [kN]

new Section 3, D.1

Note C = 0,27 in general

The web thickness can be dimensioned depending on
the size of the unstiffened web field as follows:
= 0,20 for web frame cutouts with free edges
in way of continuous longitudinals
f ⋅b 200  b2 
ts =  2 + 2 
b2 k  a 
1+ ts = web thickness of the side transverses [mm]
a2

a, b = length of side of the unstiffened web plate
new C.5.5

field, a ≥ b
f = 0,75 in general
6. Strengthenings in the fore and aft body
= 0,9 in the aft body with extreme flare and
in the fore body with flare angles α are
less or equal 40° In the fore and aft peak web frames and stringers or
tiers of beams respectively are to be arranged accord-
= 1,0 in the fore body where flare angles α ing to A.5.
are greater than 40°

new C.5.2 Note
new C.6
I - Part 1 Section 10 B Deck Beams and Supporting Deck Structures Chapter 1
GL 2012 Page 10–1

Section 10

Deck Beams and Supporting Deck Structures

A. General 2. Permissible stresses

Where the scantlings of girders not forming part of the
1. Definitions longitudinal hull structure, or of transverses, deck
k = material factor according to Section 2, B.2. beams, etc. are determined by means of strength cal-
culations the following stresses are not to be ex-
ℓ = unsupported span [m] according to Section ceeded:
3, C.
150
e = width of plating supported, measured from σb = [N / mm 2 ]
k
centre to centre of the adjacent unsupported
fields [m] 100
τ = [N / mm 2 ]
p = deck load pD, pDA or pL [kN/m2], according k
to Section 4, B. and C. 180
σv = σ2 + 3τ2 = [N / mm 2 ]
c = 0,55 k
= 0,75 for beams, girders and transverses
new A.2
which are simply supported on one or
both ends
3. Buckling strength
Ps = pillar load
The buckling strength of the deck structures is to be
= p ⋅ A + Pi [kN] examined according to Section 3, F. For this purpose
the design stresses according to Section 5, D.1. and
A = load area for one pillar [m2] the stresses due to local loads are to be considered. In
Pi = load from pillars located above the pillar the fore and aft ship region this includes also pressures
due to slamming according to Section 4, B.2.2 and
considered [kN] 2.3.
λs = degree of slenderness of the pillar

new Section 3, D.1
ℓs R eH
= ≥ 0, 2
is ⋅ π E
B. Deck Beams and Girders
ℓs = length of the pillar [cm]
1. Transverse deck beams and deck longitu-
is = radius of gyration of the pillar dinals
Is Section modulus Wd and shear area Ad of transverse
= [cm]
As deck beams and of deck longitudinals between 0,25 H
and 0,75 H above base line are to be determined by
= 0,25 ⋅ ds for solid pillars of circular the following formula:
cross section
Wd = m ⋅ c ⋅ a ⋅ p ⋅ ℓ 2 ⋅ k [cm3 ]
2 2
= 0, 25 d a + di for tubular pillars
A d = (1 − 0,817 ⋅ ma ) 0,05 ⋅ a ⋅ ℓ ⋅ p ⋅ k [cm 2 ]
Is = moment of inertia of the pillar [cm4]
As = sectional area of the pillar [cm2] m 2k
m = m 2k − ma2 ; m ≥
ds = pillar diameter [cm] 2
ma = see Section 3, A.4.
da = outside diameter of pillar [cm]
di = inside diameter of pillar [cm] mk = see Section 3, C.1.

new A.1
new B.1.1

Chapter 1 Section 10 B Deck Beams and Supporting Deck Structures I - Part 1
Page 10–2 GL 2012

2. Deck longitudinals in way of the upper and Scantlings of girders of tank decks are to be deter-
lower hull flange mined according to Section 12, B.3.#
The section modulus of deck longitudinals of decks
new B.2.3.2
located below 0,25 H and/or above 0,75 H from base
line is to be calculated according to Section 9, B. 4.3 Where a girder does not have the same sec-

new B.1.1 tion modulus throughout all girder fields, the greater
scantlings are to be maintained above the supports and
are to be reduced gradually to the smaller scantlings.
3. Attachment

new B.2.2.2
3.1 Transverse deck beams are to be connected to
the frames by brackets according to Section 3, D.2. 4.4 End attachments of girders at bulkheads are
to be so dimensioned that the bending moments and

new B.1.2.1 shear forces can be transferred. Bulkhead stiffeners
under girders are to be sufficiently dimensioned to
3.2 Deck beams crossing longitudinal walls and support the girders.
girders may be attached to the stiffeners of longitudi-
nal walls and the webs of girders respectively by
new B.2.4
welding without brackets.
4.5 Face plates are to be stiffened by tripping

new B.1.2.2 brackets according to Section 3, H.2.5. At girders of
symmetrical section, they are to be arranged alter-
3.3 Deck beams may be attached to hatchway nately on both sides of the web.
coamings and girders by double fillet welds where
there is no constraint. The length of weld is not to be
new B.2.2.3
less than 0,6 × depth of the section.
4.6 For girders in line of the deckhouse sides

new B.1.2.3 under the strength deck, see Section 16, A.3.2.

new B.2.1.1
3.4 Where deck beams are to be attached to
hatchway coamings and girders of considerable rigid-
ity (e.g. box girders), brackets are to be provided. 4.7 For girders forming part of the longitudinal
hull structure and for hatchway girders see E.

new B.1.2.4

new B.2.1.2
3.5 Within 0,6 L amidships, the arm lengths of
the beam brackets in single deck ships are to be in- 5. Supporting structure of windlasses and
creased by 20 %. The scantlings of the beam brackets chain stoppers
need, however, not be taken greater than required for
the Rule section modulus of the frames. 5.1 For the supporting structure under windlasses
and chain stoppers, the following permissible stresses

new B.1.2.5 are to be observed:
3.6 Regarding the connection of deck longitudi- 200
nals to transverses and bulkheads, Section 9, B.1. is to σb = [N / mm 2 ]
k
be observed.

new B.1.2.6 120
τ = [N / mm 2 ]
k
4. Girders and transverses
220
σv = σ2 + 3τ2 = [N / mm 2 ]
4.1 Section modulus W and shear area Aw are not k
to be less than:
new B.3.1
2 3
W = c ⋅ e ⋅ ℓ ⋅ p ⋅ k [cm ] 5.2 The acting forces are to be calculated for
2 80 % and 45 % respectively of the rated breaking load
A W = 0,05 ⋅ p ⋅ e ⋅ ℓ ⋅ k [cm ] of the chain cable, i.e.:

new B.2.2.1 – for chain stoppers 80 %

4.2 The depth of girders is not to be less than – for windlasses 80 %, where chain stoppers
1/25 of the unsupported span. The web depth of gird- are not fitted
ers scalloped for continuous deck beams is to be at – for windlasses 45 %, where chain stoppers
least 1,5 times the depth of the deck beams. are fitted
I - Part 1 Section 10 D Deck Beams and Supporting Deck Structures Chapter 1
GL 2012 Page 10–3

new B.3.2 1
=
The GL Rules for Machinery Installations (I-1-2), Sec- φ + φ2 − λs2
tion 14, D. are to be observed. See also the Rules for
Equipment (II-1-4), Section 2, Table 2.7.
φ = 0,5 1 + n p ( λs − 0, 2 ) + λs 2 

new B.3.3  
np = 0,34 for tubular and rectangular pillars
= 0,49 for open sections
C. Pillars S = safety factor
= 2,00 in general
1. General
= 1,66 in accommodation area
1.1 Structural members at heads and heels of
new C.2
pillars as well as substructures are to be constructed
according to the forces they are subjected to. The
connection is to be so dimensioned that at least 1 cm²
cross sectional area is available for 10 kN of load.
D. Cantilevers
Where pillars are affected by tension loads doublings
are not permitted. 1. General

new C.1.1
1.1 In order to withstand the bending moment
1.2 Pillars in tanks are to be checked for tension. arising from the load P, cantilevers for supporting
Tubular pillars are not permitted in tanks for flamma- girders, hatchway coamings, engine casings and un-
ble liquids. supported parts of decks are to be connected to trans-
verses, web frames, reinforced main frames, or walls.

new C.1.2

new D.1.1
1.3 For structural elements of the pillars' trans-
verse section, sufficient buckling strength according to 1.2 When determining the scantlings of the canti-
Section 3, F. has to be verified. The wall thickness of levers and the aforementioned structural elements, it is
tubular pillars which may be expected to be damaged to be taken into consideration that the cantilever bend-
during loading and unloading operations is not to be ing moment depends on the load capacity of the canti-
less than: lever, the load capacity being dependent on the ratio
of rigidity of the cantilever to that of the members
t w = 4,5 + 0,015 da [mm] for da ≤ 300 mm supported by it.

new D.1.2
= 0,03 da [mm] for da > 300 mm

new C.1.3 1.3 Face plates are to be secured against tilting

by tripping brackets fitted to the webs at suitable dis-
1.4 Pillars also loaded by bending moments have tances (see also Section 3, H.2.).
to be specially considered.
new D.1.3

new C.1.4
1.4 Particulars of calculation, together with draw-
ings of the cantilever construction are to be submitted
2. Scantlings for approval
The sectional area of pillars is not to be less than:
new D.1.4
Ps
As req = 10 ⋅ [cm 2 ] 2. Permissible stresses
σp
When determining the cantilever scantlings, the fol-
σp = permissible compressive stress [N/mm2] lowing permissible stresses are to be observed:
κ – where single cantilevers are fitted at greater
= ⋅ R eH distances:
S
bending stress:
κ = reduction factor
125
σb = [N / mm 2 ]
k
Chapter 1 Section 10 E Deck Beams and Supporting Deck Structures I - Part 1
Page 10–4 GL 2012

shear stress: bending and local bending of the longitudinal coaming

is not to exceed the following value:
80
τ = [N / mm 2 ]
k
200
– where several cantilevers are fitted at smaller σL + σℓ ≤ [N / mm 2 ]
k
distances (e.g. at every frame):
bending stress:
σℓ = local bending stress in the ship's longitudinal
150 direction
σb = [N / mm 2 ]
k
shear stress: σL = design longitudinal hull girder bending stress
according to Section 5, D.1.
100
τ = [N / mm 2 ]
k
new E.3
equivalent stress:
180 4. The equivalent stress is not to exceed the
σv = σ2 + 3τ2 = [N / mm 2 ]
k following value:
Likewise, the stresses in web frames are not to exceed
the values specified above.  L  230
σ v, all =  0,8 + [N / mm 2 ]

new D.2  450  k
for L < 90 m

E. Hatchway Girders and Girders Forming 230

Part of the Longitudinal Hull Structure = [N / mm 2 ]
k
for L ≥ 90 m
1. The scantlings of longitudinal and transverse
hatchway girders are to be determined on the basis of
strength calculations. The calculations are to be based
upon the deck loads calculated according to Section 4, σv = σ 2x + σ 2y − σ x ⋅ σ y + 3τ2
B. and C.

new E.1
σx = σ L + σℓ

2. The hatchway girders are to be so dimen-

sioned that the stress values given in Table 10.1 will σy = stress in the ship's transverse direction
not be exceeded.

new E.2 τ = shear stress
Table 10.1 Maximum stress values σℓ for hatch-
way girders 90
τmax = [N / mm 2 ]
k
Longitudinal coaming All other
and girders of the hatchway
strength deck girders The individual stresses σℓ and σy are not to exceed
150/k [N/mm2].
upper and lower flanges:

new E.4
150
σℓ = [N / mm 2 ]
k 150
σℓ = [N/mm2]
k 5. The requirements regarding strength accord-
deck level:
ing to A.3. are to be observed.
70
σℓ = [N / mm 2 ]
k
6. Weldings at the top of hatch coamings are
subject to special approval.
3. For continuous longitudinal coamings the
combined stress resulting from longitudinal hull girder
new E.5
I - Part 1 Section 11 A Watertight Bulkheads Chapter 1
GL 2012 Page 11–1

Section 11

Watertight Bulkheads

A. General
The length Lc and the distance a are to be specified in
the approval documents.
1. Watertight subdivision

new Section 27, B.3.2
1.1 All ships are to have a collision bulkhead, a
stern tube bulkhead and one watertight bulkhead at 2.1.3 If 2.1.2 is applicable, the required distances
each end of the engine room. In ships with machinery specified in 2.1.1 are to be measured from a reference
aft, the stern tube bulkhead may substitute the aft point located at a distance x forward of the F.P.
engine room bulkhead (see also 2.2).
new Section 27, B.3.3

new Section 27, B.1.1 Superstructure deck

1.2 Number and location of transverse bulkheads

fitted in addition to those specified in 1.1 are to be so Bulkhead deck
selected as to ensure sufficient transverse strength of
the hull. max. 0,08 Lc or 0,05 Lc+ 3m

new Section 27, B.1.2
min. 0,05Lc or 10m
1.3 For ships which require proof of survival
capability in damaged conditions, the watertight sub-
division will be determined by damage stability calcu-
0,85 Hc
lations. For oil tankers see Section 24, A.2., for pas-
senger vessels see Section 26, C., for special purpose x
ships see Section 27, C., for cargo ships see Section 28
and for supply vessels see Section 29, A.2. For lique-
fied gas carriers see the GL Rules for Liquefied Gas
Carriers (I-1-6), Section 2. For chemical tankers see Lc a
the GL Rules for Chemical Tankers (I-1-7), Section 2.
F. P.

new Section 27, B.2
Fig. 11.1 Location of collision bulkhead
2. Arrangement of watertight bulkheads
2.1.4 The collision bulkhead shall extend water-
2.1 Collision bulkhead tight up to the bulkhead deck. The bulkhead may have
steps or recesses provided they are within the limits
2.1.1 A collisions bulkhead shall be located at a prescribed in 2.1.1.
distance from the forward perpendicular of not less
than 0,05 Lc or 10 m, whichever is the less, and, except
new Section 27, B.3.4
as may be permitted by the Administration, not more
than 0,08 Lc or 0,05 Lc +3 m, whichever is the greater. 2.1.5 No doors, manholes, access openings, or
ventilation ducts are permitted in the collision bulk-

new Section 27, B.3.1 head below the bulkhead deck.
2.1.2 Where any part of the ship below the water-
new Section 27, B.3.5
line extends forward of the forward perpendicular,
e.g., a bulbous bow, the distance x shall be measured 2.1.6 Except as provided in 2.1.7 the collision bulk-
from a point either: head may be pierced below the bulkhead deck by not
more than one pipe for dealing with fluid in the fore-
– at the mid-length of such extension, i.e. x = 0,5 ⋅ a peak tank, provided that the pipe is fitted with a screw-
– at a distance 0,015 Lc forward of the forward down valve capable of being operated from above the
bulkhead deck, the valve chest being secured inside
perpendicular, i.e. x = 0,015 ⋅ Lc, or
the forepeak to the collision bulkhead. The Administra-
– at a distance 3 m forward of the forward per- tion may, however, authorize the fitting of this valve
pendicular, i.e. x = 3,0 m on the after side of the collision bulkhead provided
that the valve is readily accessible under all service
whichever gives the smallest measurement.
conditions and the space in which it is located is not a
Chapter 1 Section 11 A Watertight Bulkheads I - Part 1
Page 11–2 GL 2012

cargo space. All valves shall be of steel, bronze or
new Section 27, B.4.1
other approved ductile material. Valves of ordinary
cast iron or similar material are not acceptable. 2.2.2 In all cases stern tubes shall be enclosed in
watertight spaces of moderate volume. In passenger

new Section 27, B.3.6 ships the stern gland shall be situated in a watertight
shaft tunnel or other watertight space separate from
2.1.7 If the forepeak is divided to hold two differ-
the stern tube compartment and of such volume that, if
ent kinds of liquids the Administration may allow the
flooded by leakage through the stern gland, the bulk-
collision bulkhead to be pierced below the bulkhead
head deck will not be immersed. In cargo ships other
deck by two pipes, each of which is fitted as required
measures to minimize the danger of water penetrating
by 2.1.6, provided the Administration is satisfied that
into the ship in case of damage to stern tube arrange-
there is no practical alternative to the fitting of such a
ments may be taken at the discretion of the Admini-
second pipe and that, having regard to the additional
stration.
subdivision provided in the forepeak, the safety of the
ship is maintained.
new Section 27, B.4.2

new Section 27, B.3.7
3. Openings in watertight bulkheads
2.1.8 Where a long forward superstructure is fitted
the collision bulkhead shall be extended weathertight 3.1 General
to the deck next above the bulkhead deck. The exten-
sion need not be fitted directly above the bulkhead 3.1.1 Type and arrangement of doors are to be
below provided it is located within the limits pre- submitted for approval.
scribed in 2.1.1 or 2.1.3 with the exception permitted
by 2.1.9 and that the part of the deck which forms the
covered by new Section 27, B.6
step is made effectively weathertight. The extension
shall be so arranged as to preclude the possibility of 3.1.2 Regarding openings in the collision bulkhead
the bow door causing damage to it in the case of dam- see 2.1.5 and 2.1.10.
age to, or detachment of, a bow door.
covered by new Section 27, B.6

new Section 27, B.3.8
3.1.3 In the other watertight bulkheads, watertight
2.1.9 Where bow doors are fitted and a sloping doors may be fitted.
loading ramp forms part of the extension of the colli-
covered by new Section 27, B.6
sion bulkhead above the bulkhead deck, the ramp shall
be weathertight over its complete length. In cargo 3.1.4 On ships for which proof of floatability in
ships the part of the ramp which is more than 2,3 m damaged condition is to be provided, hinged doors are
above the bulkhead deck may extend forward of the permitted above the most unfavourable damage water-
limits specified in 2.1.1 or 2.1.3 Ramps not meeting line for the respective compartment only. Deviating and
the above requirements shall be disregarded as an additional requirements hereto are given in Chapter II-1
extension of the collision bulkhead. Reg. 13-1 of SOLAS (as amended by MSC.216 (82)).

new Section 27, B.3.9
covered by new Section 27, B.6
2.1.10 The number of openings in the extension of 3.1.5 For bulkhead doors in passenger ships, see
the collision bulkhead above the bulkhead deck shall Section 26, C.
be restricted to the minimum compatible with the
design and normal operation of the ship. All such
covered by new Section 27, B.6
openings shall be capable of being closed weather-
tight. 3.1.6 Watertight doors are to be sufficiently strong
and of an approved design. The thickness of plating is not

new Section 27, B.3.10 to be less than the minimum thickness according to B.2.

covered by new Section 27, B.6
2.2 Stern tube and remaining watertight bulk-
heads 3.1.7 Openings for watertight doors in the bulk-
heads are to be effectively framed such as to facilitate
2.2.1 Bulkheads shall be fitted separating the ma-
proper fitting of the doors and to guarantee perfect
chinery space from cargo and accommodation spaces
water tightness.
forward and aft and made watertight up to the bulk-
head deck. In passenger ships an afterpeak bulkhead
covered by new Section 27, B.6
shall also be fitted and made watertight up to the
bulkhead deck. The afterpeak bulkhead may, however, 3.1.8 Before being fitted, the watertight bulkhead
be stepped below the bulkhead deck, provided the doors, together with their frames, are to be tested by a
degree of safety of the ship as regards subdivision is head of water corresponding to the bulkhead deck
not thereby diminished. height. After having been fitted, the doors are to be
hose- or soap-tested for tightness and to be subjected
I - Part 1 Section 11 B Watertight Bulkheads Chapter 1
GL 2012 Page 11–3

to an operational test. Deviating and additional re- 1.3 Definitions

quirements hereto are given in Chapter II-1 Reg. 16 of
tK = corrosion addition according to Section 3, K.
SOLAS as amended.

covered by new Section 27, B.6 a = spacing of stiffeners [m]
ℓ = unsupported span [m], according to Section
3.2 Hinged doors 3, C.
Hinged doors are to be provided with rubber sealings p = 9,81 h [kN/m2]
and toggles or other approved closing appliances
which guarantee a sufficient sealing pressure. The = pc according to Section 23, E.2.3 if the ship is
toggles and closing appliances are to be operable from intended to carry dry cargo in bulk
both sides of the bulkhead. Hinges are to have oblong
h = distance from the load centre of the structure
holes. Bolts and bearings are to be of corrosion resis-
to a point 1 m above the bulkhead deck at the
tant material. A warning notice requiring the doors to
ship's side, for the collision bulkhead to a
be kept closed at sea is to be fitted at the doors.
point 1 m above the upper edge of the colli-

covered by new Section 27, B.6 sion bulkhead at the ship's side
For cargo ships with proven damage stability
3.3 Sliding doors see Section 28, D.2.
Sliding doors are to be carefully fitted and are to be For the definition of "load centre" see Section
properly guided in all positions. Heat sensitive materi- 4, A.2.1
als are not to be used in systems which penetrate wa-
tertight subdivision bulkheads, where deterioration of cp, cs = coefficients according to Table 11.1
such systems in the event of fire would impair the 235
watertight integrity of the bulkheads. f =
R eH
The closing mechanism is to be safely operable from
each side of the bulkhead and from above the free-
new A.2
board deck. If closing of the door cannot be observed
with certainty, an indicator is to be fitted which shows, Table 11.1 Coefficients cp and cs
if the door is closed or open; the indicator is to be
installed at the position from which the closing Coefficients cp and cs Collision Other
mechanism is operated. bulkhead bulkheads

covered by new Section 27, B.6 Plating cp 1,1 f 0,9 f

cs: in case of
3.4 Penetrations through watertight bulkheads constraint of 0,33 ⋅ f 0,265 ⋅ f
Where bulkhead fittings are penetrating watertight both ends
bulkheads, care is to be taken to maintain water tight- Stiffeners, cs: in case of simple
ness by observation of Chapter II-1 Reg. 12 of SOLAS corrugated support of one
as amended. For penetrations through the collision bulkhead end and 0,45 ⋅ f 0,36 ⋅ f
bulkhead, 2.1.6 is to be observed. elements constraint at the
other end

covered by new Section 27, B.6
cs: both ends simply
supported 0,66 ⋅ f 0,53 ⋅ f

For the definition of "constraint" and "simply supported",

B. Scantlings see Section 3, D.1.

1. General, Definitions
2. Bulkhead plating
1.1 Where holds are intended to be filled with
2.1 The thickness of the bulkhead plating is not
ballast water, their bulkheads are to comply with the
to be less than:
requirements of Section 12.

new A.1.1 t = cp ⋅ a p + tK [mm]
t min = 6, 0 f [mm]
1.2 Bulkheads of holds intended to be used for
carrying dry cargo in bulk with a density ρc > 1,0 are
to comply with the requirements of Section 23., as far For ships with large deck openings according to
Section 5, F.1.2, the plate thickness of transverse bulk-
as their strength is concerned.
heads is not to be less than:

new A.1.2
Chapter 1 Section 11 B Watertight Bulkheads I - Part 1
Page 11–4 GL 2012

3.2 In horizontal part of bulkheads, the stiffeners

∆ℓ H H 
t = c⋅ ⋅  −T +T2 + tK [mm] are also to comply with the rules for deck beams ac-
3  1 1  22  cording to Section 10.
F1 ⋅ ReH ⋅ 2 + 2 
a b 
new C.2

∆ℓ = distance from the mid of hold before to the 3.3 The scantlings of the brackets are to be de-
mid of hold aft of the considered transverse termined in dependence of the section modulus of the
bulkhead or supporting bulkhead [m] stiffeners according to Section 3, D.2. If the length of
the stiffener is 3,5 m and over, the brackets are to
a, b = spacing of stiffeners [m] extend to the next beam or the next floor.
tK = corrosion addition [mm] according to Section
new C.3
3, K.
3.4 Unbracketed bulkhead stiffeners are to be
F1 = correction factor according to Section 3, F.1. connected to the decks by welding. The length of weld
is to be at least 0,6 × depth of the section.
c = 13 in general

new C.4
= 15 below z = 0,2 H and above 0,8 H and
3.5 If the length of stiffeners between bulkhead
generally in the fore ship before x/L = 0,8
deck and the deck below is 3 m and less, no end at-

new B.1 tachment according to 3.4 is required. In this case the
stiffeners are to be extended to about 25 mm from the
deck and sniped at the ends, see also Section 3, D.3.
2.2 In small ships, the thickness of the bulkhead
plating needs not exceed the thickness of the shell plating
new C.5
for a frame spacing corresponding to the stiffener spacing.
3.6 Bulkhead stiffeners cut in way of watertight
2.3 The stern tube bulkhead is to be provided doors are to be supported by carlings or stiffeners.
with a strengthened plate in way of the stern tube.
new C.6

new B.2
4. Corrugated bulkheads
2.4 In areas where concentrated loads due to ship
4.1 The plate thickness of corrugated bulkheads
manoeuvres at terminals may be expected, the buck-
is not to be less than required according to 2.1.
ling strength of bulkhead plate fields directly attached
to the side shell, is to be examined according to For the spacing a [m] the greater one of the values b or
Section 9, B.4.4 and 4.5. s according to 4.3 is to be taken.

new B.3
new F.1

4.2 The section modulus of a corrugated bulkhead

2.5 When determining the bulkhead scantlings of
element is to be determined according to 3.1. For the
tanks, connected by cross-flooding arrangements, the
spacing a [m] the width of an element e, according to 4.3
increase in pressure head at the immerged side that
is to be taken. For the end attachment see Section 3, D.4.
may occur at maximum heeling in the damaged condi-
tion shall be taken into account.
new F.2

new B.4 4.3 The actual section modulus of a corrugated
bulkhead element is to be assessed according to the
3. Stiffeners following formula:
 s
W = t ⋅ d  b +  [cm3 ]
3.1 The section modulus of bulkhead stiffeners is  3
not to be less than:
b
W = m ⋅ cs ⋅ a ⋅ ℓ 2 ⋅ p [cm3 ] b
2
s

m 2k
d
a

m = m 2k − ma2 ; m ≥
2
ma = see Section 3, A.4. e

mk = see Section 3, C.1. Fig. 11.2 Element of a corrugated bulkhead

new C.1
I - Part 1 Section 11 B Watertight Bulkheads Chapter 1
GL 2012 Page 11–5

e = width of element [cm] k = material factor according Section 2, B.2.

b = breadth of face plate [cm]
new D.2.1
s = breadth of web plate [cm] If necessary Section 5, F.2. shall be observed in addi-
tion.
d = distance between face plates [cm]
t = plate thickness [cm] 5.3.2 Load case "hold flooding"
α ≥ 45° The thickness of webs shall not be smaller than:

new F.3 1000 ⋅ Q
tw = + t K [mm]
τzul ⋅ h w
4.4 For watertight bulkheads of corrugated type
on ships according to Section 5, G. see Section 23, E.
Q  b2  R

new F.4 τzul = 727 ReH 1 + 0,75  ≤ eH [N/mm]
2
b ⋅ hw  2
a 2,08

5. Primary supporting members
Q = shear force [kN]
5.1 General hw = height of web [mm]
Primary supporting members are to be dimensioned a, b = lengths of stiffeners of the unstiffened web
using direct calculation as to ensure the stress criteria field, where hw ≥ b ≤ a
according to 5.3.1 for normal operation and the crite-
ria according to 5.3.2 if any cargo hold is flooded.
new D.2.2

new D.1.1 5.3.3 Dimensioning of primary supporting
Regarding effective breadth and buckling proof in members
each case Section 3, E. and F. has to be observed. For dimensioning of primary supporting members

new Section3, D.1 plastic hinges can be taken into account.
This can be done either by a non-linear calculation of
In areas with cut-outs 2nd-order bending moments
the total bulkhead or by a linear girder grillage calcu-
shall be taken into account.
lation of the idealised bulkhead.

new D.1.3 When a linear girder grillage calculation is done, only
those moments and shear forces are taken as boundary
5.2 Load assumptions conditions at the supports, which can be absorbed by
the relevant sections at these locations in full plastic
5.2.1 Loads during operation condition.
Loads during operation are the external water pres-
new D.1.1
sure, see Section 4, and the loads due to cargo and
filled tanks, see Section 17, B.1.6, Section 21, G. and The plastic moments [kNm] are calculated by:
if relevant depending on the deck opening Section 5,
F. Wp ⋅ R eH
Mp =

new D.2.1 c ⋅ 1 200

5.2.2 Loads in damaged condition c = 1,1 for the collision bulkhead

The loads in case of hold flooding result from 1.3 = 1,0 for cargo hold bulkheads
considering Section 28, D.2. The plastic shear forces [kN] are calculated by:

new D.2.2 As ⋅ R eH
Qp =
5.3 Strength criteria c ⋅ 2 080

new D.3
5.3.1 Load case "operation"
For the field moments and shear forces resulting thereof
With loads according to 5.2.1 the following permissi-
the sections are defined in such a way that the condition
ble stresses are to be used:
σv ≤ R eH
2
σv = σ N + 3 τ2 ≤ 180 / k [N/mm2]
is fulfilled.
σN = normal stress, σN ≤ 150 / k [N/mm2]
new D.2.1
τ = shear stress, τ ≤ 100 / k [N/mm2]
Chapter 1 Section 11 C Watertight Bulkheads I - Part 1
Page 11–6 GL 2012

The plastic section moduli are to be calculated as complying with the requirements according to A.3.3.
follows: For extremely short shaft tunnels watertight doors
n between tunnel and engine room may be dispensed
1
Wp = ∑ Ai ⋅ epi [cm3 ] with subject to special approval.
1000 i = 1

epi = distance [mm] of the centre of the partial area In this connection see also Chapter II-1, Regulation
Ai from the neutral axis of the yielded section. 11/8 of SOLAS as amended.
The neutral axis shall not be taken in a position
lower than the lowest point of the web.
new Section 27, D.4.2
Ai = effective partial area [mm2] considering Sec-
tion 3, F.2.2. 1.3 Tunnel ventilators and the emergency exit are
In this connection the area As of webs transferring to be constructed watertight up to the freeboard deck.
shear shall not be taken into account.
That part of the web height related to shear transfer
new Section 27, D.4.3
shall not be less than:
tw 2. Scantlings
∆ hw = hw ⋅
t wa

twa = as built thickness of the web ≥ tw 2.1 The plating of the shaft tunnel is to be dimen-
sioned as for a bulkhead according to B.2.1.
Where girders are built up by partial areas Ai with
different yield strength ReHi the plastic moments are
calculated by:
new G.1.1
n
∑ Ai ⋅ R eHi ⋅ e pi
i =1 2.2 The plating of the round part of tunnel tops
Mp = [kNm]
c ⋅ 1, 2 ⋅ 10 6 may be 10 per cent less in thickness.

The plastic shear forces are:

new G.1.2
n
∑ Asi ⋅ R eHi
i =1 2.3 In the range of hatches, the plating of the
Qp = [kN]
c ⋅ 2080 tunnel top is to be strengthened by not less than 2 mm
unless protected by a ceiling.

new D.3
On containerships this strengthening can be dispensed
6. Watertight longitudinal structures with.
The plating and stiffeners of watertight longitudinal
structures shall be dimensioned according to Table
new G.1.3
11.1, column "Other bulkheads".

new E
2.4 The section modulus of shaft tunnel stiffeners
is to be determined according to B.3.1.

C. Shaft Tunnels
new G.1.4

1. General
2.5 Horizontal parts of the tunnel are to be
1.1 Shaft and stuffing box are to be accessible. treated as horizontal parts of bulkheads and as cargo
Where one or more compartments are situated be- decks respectively.
tween stern tube bulkhead and engine room, a water-
tight shaft tunnel is to be arranged. The size of the
new G.1.5
shaft tunnel is to be adequate for service and mainte-
nance purposes.

new Section 27, D.4.1 2.6 Shaft tunnels in tanks are to comply with the
requirements of Section 12.
1.2 The access opening between engine room and
shaft tunnel is to be closed by a watertight sliding door
new G.1.6
I - Part 1 Section 12 A Tank Structures Chapter 1
GL 2012 Page 12–1

Section 12

Tank Structures

A. General
4.2 For pumping and piping, see also the GL
Note Rules for Machinery Installations (I-1-2), Section 11.
For oil fuel tanks see also the Rules for Machinery
The arrangement and subdivision of fuel oil tanks has
Installations (I-1-2), Section 10. For tanks in the dou-
to be in compliance with MARPOL, Annex I, Reg.
ble bottom, see Section 8, B.5.
12 A "Oil Fuel Tank Protection".
4.3 For cargo oil tanks see Section 24.

new Sectionn 27, C.3.1.2

new A.1.2

1. Subdivision of tanks 4.4 For dry cargo holds which are also intended
to be used as ballast water tanks, see C.2.
1.1 In tanks extending over the full breadth of
the ship intended to be used for partial filling, (e.g. oil
new A.1.3
fuel and fresh water tanks), at least one longitudinal
bulkhead is to be fitted, which may be a swash bulk- 4.5 Where tanks are provided with cross flooding
head. arrangements the increase of the pressure head is to be
taken into consideration (see also Section 28, F.).

new Sectionn 27, B.7.1

new A.1.4
1.2 Where the forepeak is intended to be used as
tank, at least one complete or partial longitudinal 5. Separation of oil fuel tanks from tanks for
swash bulkhead is to be fitted, if the tank breadth other liquids
exceeds 0,5 B or 6 m, whichever is the greater.
5.1 Oil fuel tanks are to be separated from tanks
When the afterpeak is intended to be used as tank, at
least one complete or partial longitudinal swash bulk- for lubricating oil, hydraulic oil, thermal oil, vegetable
head is to be fitted. The largest breadth of the liquid oil, feedwater, condensate water and potable water by
cofferdams.
surface should not exceed 0,3 B in the aft peak.

new Sectionn 27, C.3.2.1

new Sectionn 27, B.7.2
5.2 Upon special approval on small ships the
1.3 Peak tanks exceeding 0,06 L or 6 m in length,
whichever is greater, shall be provided with a trans- arrangement of cofferdams between oil fuel and lub-
ricating oil tanks may be dispensed with provided
verse swash bulkhead.
that:

new Sectionn 27, B.7.3
– the common boundary is continuous, i.e. it does
not abut at the adjacent tank boundaries, see Fig.
2. Air, overflow and sounding pipes 12.1
For the arrangement of pipes see Section 21, E. Where the common boundary cannot be con-

new A.1.1 structed continuously according to Fig. 12.1, the
fillet welds on both sides of the common bound-
ary are to be welded in two layers and the throat
3. Forepeak tank thickness is not to be less than 0,5 ⋅ t (t = plate
Oil is not to be carried in a forepeak tank. See also thickness).
SOLAS 74, Chapter II-2, Reg. 15.6 and MARPOL – Stiffeners or pipes do not penetrate the common
73/78, Annex I, Reg. 14.4. boundary.

new Sectionn 27, C.3.5.5
– The corrosion allowance tK for the common
boundary is not less than 2,5 mm.
4. Cross references

new Sectionn 27, C.3.2.2
4.1 Where a tank bulkhead forms part of a water-
tight bulkhead, its strength is not to be less than re-
quired by Section 11.
Chapter 1 Section 12 A Tank Structures I - Part 1
Page 12–2 GL 2012

new B.1.3

7.3 For ballast tanks of dry cargo ships tmin need

common
boundary not be taken greater than 9,0 mm.

new B.1.3

7.4 For oil tankers see Section 24, A.14.

new B.1.3

Fig. 12.1 Continuous common boundary replac-

ing a cofferdam 8. Plating and stiffeners in the propeller area
and in the engine room
5.3 Fuel oil tanks adjacent to lubricating oil cir-
culation tanks are not permitted. 8.1 General

new Sectionn 27, C.3.2.3 From a vibration point of view tank structures in the
vicinity of the propeller(s) and the main engine should
5.4 For fuel oil tanks which are heated up to a be designed such that the design criteria defined in 8.3
temperature which is higher than the flash point – to 8.4 are fulfilled (see also Section 6, F.1. and Sec-
10 °C of the relevant fuel, the GL Rules for Machin- tion 8, A.1.2.3).
ery Installations (I-1-2), Section 10, B.5. are to be ob-
new B.6.1
served specifically.

new Sectionn 27, C.3.2.4 8.2 Definitions

fplate 1 = lowest natural frequency of isotropic

6. Tanks for heated liquids plate field under consideration of addi-
tional outfitting and hydrodynamic mas-
6.1 Where heated liquids are intended to be car- ses [Hz]
ried in tanks, a calculation of thermal stresses is re-
quired, if the carriage temperature of the liquid ex- fstiff 1 = lowest natural frequency of stiffener un-
ceeds the following values: der consideration of additional outfitting
T = 65 °C in case of longitudinal framing and hydrodynamic masses [Hz]

= 80 °C in case of transverse framing dp = propeller diameter [m]

new I.1 r = distance of plate field or stiffener to 12
o'clock propeller blade tip position [m]
6.2 The calculations are to be carried out for both
temperatures, the actual carriage temperature and the r
dr = ratio
limit temperature T according to 6.1. dp
The calculations are to give the resultant stresses in
P
the hull structure based on a sea water temperature of α =
0 °C and an air temperature of 5 °C. ∆
Constructional measures and/or strengthenings will be P = nominal main engines output [kW]
required on the basis of the results of the calculation
for both temperatures. ∆ = ship's design displacement [ton]

new I.2 n = maximum propeller shaft revolution rate
[1/min]
7. Minimum thickness
z = number of propeller blades
7.1 The thickness of all structures in tanks is not
to be less than the following minimum value: fblade = propeller blade passage excitation fre-
quency at n [Hz]
t min = 5,5 + 0, 02 L [mm]

new B.1.3
1 The natural frequencies of plate fields and stiffeners can be
7.2 For fuel oil, lubrication oil and freshwater estimated by POSEIDON or by means of the software tool
tanks tmin need not be taken greater than 7,5 mm. GL LocVibs which can be downloaded from the GL homepage
www.gl-group.com/en/gltools/GL-Tools.php.
I - Part 1 Section 12 B Tank Structures Chapter 1
GL 2012 Page 12–3

1 B. Scantlings
= ⋅ n ⋅ z [ Hz ]
60
1. Definitions
ne = maximum main engine revolution rate
[1/min] k = material factor according to Section 2, B.2.

nc = number of cylinders of main engine a = spacing of stiffeners or load width [m]

kstroke = number indicating the type of main engine ℓ = unsupported span [m] according to Section 3,
C.
= 1,0 for 2-stroke (slow-running) main
engines p = load p1 or pd [kN/m2] according to Section 4,
D.; the greater load to be taken.
= 0,5 for 4-stroke (medium speed) main
engines 2 For tank structures on the shell the pressure p below
Tmin need not be larger than:
fignition = main engine ignition frequency at ne
 z  2
1 p = p1 − 10 ( Tmin − z ) + p0 ⋅ cF 1 +  [kN/m ]
= ⋅ k stroke ⋅ nc ⋅ ne [ Hz ]  Tmin 
60
with p ≤ P1

new B.6.2
8.3 Tank structures in propeller area
Tmin = smallest design ballast draught [m]
For vessels with a single propeller, plate fields and
stiffeners of tank structures should fulfil the following z = distance of structural member above base line
frequency criteria: [m]

for α ≥ 0.3 p2 = load [kN/m2] according to Section 4, D.1.

0 < dr ≤ 1 1 < dr ≤ 2 2 < dr ≤ 4 4 < dr ≤ 6 tK = corrosion addition according to Section 3, K.

fplate > 4,40 ⋅ fblade 3,45 ⋅ fblade 2,40 ⋅ fblade 1,20 ⋅ fblade h = filling height of tank [m]
et = characteristic tank dimension ℓt or bt [m]
fstiff > 4,40 ⋅ fblade 3,45 ⋅ fblade 2,40 ⋅ fblade 1,20 ⋅ fblade
ℓt = tank length [m]
for α < 0.3
bt = tank breadth [m]
0 < dr ≤ 2 2 < dr ≤ 4
2
fplate > 2,40 ⋅ fblade 1,20 ⋅ fblade  235  2
σ pℓ =  k  − 3 ⋅ τL − 0,89 ⋅ σ L [N / mm 2 ]
fstiff >2,40⋅ fblade 1,20 ⋅ fblade  

new B.6.3 σL = membrane stress at the position considered

[N/mm2] according to Section 5, D.1.
8.4 Tank structures in main engine area
τL = shear stress [N/mm2] at the position consid-
For vessels with a single propeller, plate fields and
stiffeners of tanks located in the engine room should at ered see also Section 5, D.1.
all filling states fulfil the frequency criteria as summa- nf = 1,0 for transverse stiffening
rised in Table 12.1.
Generally, direct connections between transverse en- = 0,83 for longitudinal stiffening
gine top bracings and tank structures shall be
For the terms "constraint" and "simply supported" see
avoided. Pipe fittings at tank walls etc. shall be de-
signed in such a way that the same frequency criteria Section 3, D.
as given for plates are fulfilled.
new A.2

new B.6.4

2 The number is valid for in-line engines. The ignition frequency

for V-engines depends on the V-angle of the cylinder banks
and can be obtained from the engine manufacturer.
Chapter 1 Section 12 B Tank Structures I - Part 1
Page 12–4 GL 2012

Table 12.1 Frequency criteria

Engine type Mounting type Application area Frequency criteria

f plate > 1,2 ⋅ fignition

f stiff > 1,2 ⋅ fignition

Tanks within
Slow-speed Rigid engine room and
f plate < 1,8 ⋅ fignition or

f plate > 2,2 ⋅ fignition

f plate < 0,8 ⋅ fignition or

f plate > 1,2 ⋅ fignition

Tanks within
Rigid or semi-resilient engine room
f stiff < 0,8 ⋅ fignition or

Medium-speed f stiff > 1,2 ⋅ fignition

Tanks within
engine length f plate < 0,9 ⋅ fignition or
Resilient up to next
platform deck f plate > 1,1 ⋅ fignition
above inner bottom

2. Plating 3. Stiffeners and girders

2.1 The plate thickness is not to be less than: 3.1 Stiffeners and girders, which are not con-
sidered as longitudinal strength members

t1 = 1,1 ⋅ a ⋅ p ⋅ k + tK [mm] 3.1.1 The section modulus of stiffeners and girders

constrained at their ends, is not to be less than:
t 2 = 0,9 ⋅ a ⋅ p2 ⋅ k + t K [mm]
W1 = 0,55 ⋅ m ⋅ a ⋅ ℓ 2 ⋅ p ⋅ k [cm3 ]

new B.1.1
W2 = 0, 44 ⋅ m ⋅ a ⋅ ℓ 2 ⋅ p 2 ⋅ k [cm3 ]
2.2 Above the requirements specified in 2.1 the
Where one or both ends are simply supported, the
thickness of tank boundaries (including deck and inner
section moduli are to be increased by 50 per cent.
bottom) carrying also normal and shear stresses due to
longitudinal hull girder bending is not to be less than: The shear area of the girder webs is not to be less
than:
p A w1 = (1 − 0,817 ⋅ m a ) ⋅ 0, 05 ⋅ a ⋅ ℓ ⋅ p ⋅ k [cm 2 ]
t = 16,8 ⋅ n f ⋅ a + tK [mm]
σ pℓ
A w 2 = (1 − 0,817 ⋅ m a ) ⋅ 0, 04 ⋅ a ⋅ ℓ ⋅ p 2 ⋅ k [cm 2 ]

new B.1.2
In case of girders supporting longitudinal stiffeners
2.3 Proof of plating of buckling strength of longi- and in case of heel stiffeners the factors m = 1 and ma
tudinal and transverse bulkheads is to be carried out = 0 are to be used. Otherwise these factors are to be
according to Section 3, F. For longitudinal bulkheads determined according to Section 9, B.2. as for longitu-
the design stresses according to Section 5, D.1. and dinals.
the stresses due to local loads are to be considered.
Aw2 is to be increased by 50 per cent at the position of

new Section3, D.1 constraint for a length of 0,1 ℓ.
I - Part 1 Section 12 B Tank Structures Chapter 1
GL 2012 Page 12–5

new B.2.2.1 3.5 The stiffeners of tank bulkheads are to be

attached at their ends by brackets according to Section
The buckling strength of the webs is to be checked 3, D.2. The scantlings of the brackets are to be deter-
according to Section 3, F. mined according to the section modulus of the stiffen-
ers. Brackets have to be fitted where the length of the

new Section3, D.1 stiffeners exceeds 2 m.
The brackets of stiffeners are to extend to the next
3.1.2 Where the scantlings of stiffeners and girders
beam, the next floor, the next frame, or are to be oth-
are determined according to strength calculations, the
erwise supported at their ends.
following permissible stress values apply:

new B.2.3.2
– if subjected to load p:
3.6 Where stringers of transverse bulkheads are
150 2 supported at longitudinal bulkheads or at the side
σb = [N / mm ]
k shell, the supporting forces of these stringers are to be
considered when determining the shear stress in the
100 longitudinal bulkheads. Likewise, where vertical gird-
τ = [N / mm 2 ] ers of transverse bulkheads are supported at deck or
k inner bottom, the supporting forces of these vertical
girders are to be considered when determining the
180 shear stresses in the deck or inner bottom respectively.
σv = σ2b + 3τ2 = [N / mm 2 ]
k
The shear stress introduced by the stringer into the
– if subjected to load p2: longitudinal bulkhead or side shell may be determined
by the following formula:

180 PSt
σb = [N / mm2 ] τSt = [N / mm 2 ]
k 2 ⋅ bSt ⋅ t

115 PSt = supporting force of stringer or vertical girder

τ = [N / mm 2 ]
k [kN]
bSt = breadth of stringer or depth of vertical girder
200
σv = σ2b + 3τ2 = [N / mm 2 ] including end bracket (if any) [m] at the sup-
k porting point

new B.2.2.2 t = see 2.2

3.2 Stiffeners and girders, which are to be con- The additional shear stress τSt is to be added to the
sidered as longitudinal strength members shear stress τL due to longitudinal bending according
to Section 5, D.1. in the following area:
3.2.1 The section moduli and shear areas of hori- – 0,5 m on both sides of the stringer in the ship's
zontal stiffeners and girders are to be determined ac- longitudinal direction
cording to Section 9, B.3.1 as for longitudinals. In this
case for girders supporting transverse stiffeners the – 0,25 × bSt above and below the stringer
factors m = 1 and ma = 0 are to be used.
Thereby the following requirement shall be satisfied:

new B.2.3.1
110 PSt
≥ + τL
3.2.2 Regarding buckling strength of girders the k 2 ⋅ bSt ⋅ t
requirements of 2.3 are to be observed.

new Section 5, E.7

new Section3, D.1
3.7 Connection between primary support
3.3 The scantlings of beams and girders of tank members and intersecting stiffeners
decks are also to comply with the requirements of
Section 10. 3.7.1 At intersections of stiffeners with primary
support members the shear connection and attached

new B.2.1 heel stiffeners are to be designed acc. to Section 9, B.4.
subjected to tank loads p and p2.
3.4 For frames in tanks, see Section 9, A.2.2.
new B.2.4
Chapter 1 Section 12 B Tank Structures I - Part 1
Page 12–6 GL 2012

3.7.2 The cross-sectional areas of a heel stiffener
new B.2.4

are to be such that the calculated stresses do not ex-
ceed the permissible stresses. 3.7.4 The cross-sectional area of a collar plate is to
be such that the calculated bending stress does not
– normal stress at minimum heel stiffener cross- exceed the permissible stresses.
sectional area:
– bending stress of collar plate
103 ⋅ Ph 150
σaxial = ≤ for load p [N/mm2] 3 ⋅103 ⋅ Pc ⋅ bc 150
ℓh ⋅ th k σc = ≤ for load p [N/mm2]
h c2 ⋅ tc k
180 180
≤ for load p2 ≤ for load p2
k k
– normal stress in the fillet weld connection of – bending stress in the fillet weld connection of the
heel stiffener: collar plate
103 ⋅ Ph 1,5 ⋅103 ⋅ Pc ⋅ bc
σweld = ≤ σ vp for load p [N/mm2] σ weld,c = ≤ σ vp for load p [N/mm2]
2 ⋅ a ⋅ ( ℓ hc + t h + a ) h c2 ⋅ a

σ vp σ vp
≤ for load p2 ≤ for load p2
0,8 0,8
a, σvp according to 3.7.2
a = throat thickness [mm] of fillet weld, see Sec-
tion 19, B.3.3
new B.2.4
σvp = permissible equivalent stress in the fillet weld
4. Corrugated bulkheads
acc. to Section 19, Table 19.2

new B.2.4 4.1 The plate thicknesses of corrugated bulkheads
as well as the required section moduli of corrugated
3.7.3 The cross-sectional areas of the shear con- bulkhead elements are to be determined according to 2.
nections are to be such that the calculated stresses do and 3., proceeding analogously to Section 11, B.4.
not exceed the permissible stresses.
The plate thickness is not to be less than tmin accord-
– shear stress in the shear connections to the ing to A.7., or
transverse support member:
– if subjected to load p
3
10 ⋅ Pi 100 b
τi = ≤ for load p [N/mm2] t krit. = σD + t K [mm]
hi ⋅ ti k 905
– if subjected to load p2
115
≤ for load p2
k b
t krit. = σD + t K [mm]
960
– shear stress in the shear connections in way of
fillet welds: σD = compressive stress [N/mm2]
b = breadth of face plate strip [mm]
103 ⋅ Pi
τ weld,i = ≤ τp for load p [N/mm2]
new B.4.1
2 ⋅ a ⋅ hi
4.2 For the end attachment Section 3, D.4. is to
τp be observed.
≤ for load p2
0,8
new B.4.2

τp = permissible shear stress in the fillet weld acc.

5. Thickness of clad plating
to Section 19, Table 19.2
i = s for the shear connection of longitudinal and 5.1 Where the yield strength of the cladding is
transverse support member not less than that of the base material the plate thick-
ness is to be determined according to 2.1.
= c for the shear connection of longitudinal and
collar plate
new B.5.1
I - Part 1 Section 12 D Tank Structures Chapter 1
GL 2012 Page 12–7

5.2 Where the yield strength of the cladding is et

less than that of the base material the plate thickness is Tℓ, b = 1,132 [s]
not to be less than: f
f = hyperbolic function as follows:
k
t1 = 0,55 ⋅ a p ⋅ + tK [mm]
A π⋅h
= tanh  
 et 
k
t 2 = 0, 45 ⋅ a p2 ⋅ + t K [mm] Period of wave excited pitch motion:
A
for one side clad steel: L
Ts = [s]
1,17 ⋅ L + 0,15 ⋅ v0
tp  tp 2 
A = 0, 25 −  1 − r −
2t  2t
(1 − r )  v0 = ahead speed of ship [kn] as defined in Section
1, H.5.
for both side clad steel: Period of roll motion:

tp  tp  cr ⋅ B
A = 0, 25 − 1 −  (1 − r ) Tr = [s]
t  t  GM
cr = 0,78 in general
t = plate thickness including cladding [mm]
= 0,70 for tankers in ballast
tp = thickness of the cladding [mm]
R ep GM ≈ 0,07 ⋅ B in general
r =
R eH ≈ 0,12 ⋅ B for tankers and bulkcarriers

Rep = yield strength [N/mm2] of the cladding at
new C.1

service temperature
2. Hold spaces for ballast water
ReH = yield strength of the base material [N/mm2]
according to Section 2, B.2. In addition to the requirements specified under 1.
above for hold spaces of dry cargo ships and bulk

new B.5.2 carriers, which are intended to be filled with ballast
water, the following is to be observed:
5.3 The plate thicknesses determined in accord-
ance with 5.1 and 5.2 respectively may be reduced by – For hold spaces only permitted to be completely
0,5 mm. For chemical tankers however the reductions filled, a relevant notice will be entered into the
as per GL Rules for Chemical Tankers (I-1-7), Section Certificate.
4, 4-0.1.3 apply. – Adequate venting of the hold spaces and of the
hatchway trunks is to be provided.

new B.5.3
– For frames also Section 9, A.2.2 is to be observed.

new C.2
C. Tanks with Large Lengths or Breadths

1. General D. Vegetable Oil Tanks

Tanks with lengths ℓt > 0,1 L or breadths bt > 0,6 B 1. Further to the regulations stipulated under A.
(e.g. hold spaces for ballast water) which are intended and B. for vegetable oil tanks, the following require-
to be partially filled, are to be investigated to avoid ments are to be observed.
resonance between the liquid motion and the pitch or
new D.1
roll motion of the ship. If necessary, critical tank filling
ratios are to be avoided. The ship's periods of pitch and 2. Tanks carrying vegetable oil or similar liq-
roll motion as well as the natural periods of the liquid uids, the scantlings of which are determined according
in the tank may be determined by the following for- to B., are to be either fully loaded or empty. A corre-
mulae: sponding note will be entered into the Certificate.
Natural period of liquid in tank: These tanks may be partially filled provided they are
subdivided according to A.1.2. Filling ratios between
70 and 90 per cent should be avoided.
Chapter 1 Section 12 G Tank Structures I - Part 1
Page 12–8 GL 2012

new D.2 a point 2,5 m above tank top, whichever is

the greater.
3. In tanks carrying vegetable oil or similar liquids
sufficient air pipes are to be fitted for pressure equaliz- For tanks intended to carry liquids of a density greater
ing. Expansion trunks of about 1 per cent of the tank than 1 t/m3, the head h is at least to be measured to a
volume are to be provided. Where the tank is subdivided level at the following distance hp above tank top:
by at least one centre line bulkhead, 3 per cent of the tank
may remain empty and be used as expansion space. hp = 2,5 ⋅ ρ [mWS], head of water [m]

new D.3
new E.2.2

2.3 For minimum thickness the requirements of

E. Detached Tanks A.7. apply in general.

new E.2.3
1. General

1.1 Detached tanks are to be adequately secured

against forces due to the ship's motions. F. Potable Water Tanks

new E.1.1
1. Potable water tanks shall be separated from
1.2 Detached tanks in hold spaces are also to be pro- tanks containing liquids other than potable water,
vided with antifloatation devices. It is to be assumed that ballast water, distillate or feed water.
the hold spaces are flooded to the load water line. The
stresses in the antifloatation devices caused by the floata-
new F.1
tion forces are not to exceed the material's yield strength.
2. In no case sanitary arrangement or corre-

new E.1.2 sponding piping are to be fitted directly above the
potable water tanks.
1.3 Detached oil fuel tanks should not be in-
stalled in cargo holds. Where such an arrangement
new F.2
cannot be avoided, provision is to be made to ensure
that the cargo cannot be damaged by leakage oil. 3. Manholes arranged in the tank top are to have

new E.1.3 sills.

new F.3
1.4 Fittings and pipings on detached tanks are to
be protected by battens, and gutter ways are to be fitted 4. If pipes carrying liquids other than potable
on the outside of tanks for draining any leakage oil. water are to be led through potable water tanks, they

new E.1.4 are to be fitted in a pipe tunnel.

new F.4
2. Scantlings
5. Air and overflow pipes of potable water tanks
2.1 The thickness of plating of detached tanks is are to be separated from pipes of other tanks.
to be determined according to B.2.1 using the formula
for t1 and the pressure p as defined in 2.2.
new F.5
G. Swash Bulkheads

new E.2.1

2.2 The section modulus of stiffeners of detached 1. The total area of perforation shall not be less
tanks is not to be less than: than 5 % and should not exceed 10 % of the total
bulkhead area.
W = c ⋅ a ⋅ ℓ 2 ⋅ p ⋅ k [cm3 ]
new G.1

c = 0,36 if stiffeners are constrained at both 2. The plate thickness shall, in general, be equal
ends to the minimum thickness according to A.7. Strength-
= 0,54 if one or both ends are simply sup- enings may be required for load bearing structural
ported parts.

p = 9,81 ⋅ h [kN/m2] The free lower edge of a swash bulkhead is to be ade-

quately stiffened.
h = distance from load centre of plate panel or
stiffener respectively to top of overflow or to
new G.2
I - Part 1 Section 12 G Tank Structures Chapter 1
GL 2012 Page 12–9

new G.3
3. The section modulus of the stiffeners and
girders is not to be less than W1 as per B.3., however, 4. For swash bulkheads in oil tankers see also
in lieu of p the load pd according to Section 4, D.2., Section 24, D.
but disregarding pv is to be taken.

new G.4
I - Part 1 Section 13 C Stem and Sternframe Structures Chapter 1
GL 2012 Page 13–1

Section 13

Stem and Sternframe Structures

A. Definitions
Dimensioning of the stiffening has to be done accord-
k = material factor according to Section 2, B.2.1, ing to Section 9.
for cast steel k = kr according to Section 14,

new B.2.2.1
A.4.2
CR = rudder force [N] according to Section 14, B.1. 2.2 Starting from 600 mm above the load water-
line up to T + c0, the thickness may gradually be re-
B1 = support force [N] according to Section 14, C.3.
duced to 0,8 t.
tK = corrosion addition [mm] according to Section
new B.2.1.3
3, K. 2.3 Plate stems and bulbous bows have to be

new A.1 stiffened by fore-hooks and/or cant frames. In case of
large and long bulbous bows, see Section 9, A.5.3.3.
aB = spacing of fore-hooks [m]

new B.2.2.2

new B.2.1.1

C. Sternframe
B. Stem
1. General
1. Bar stem
1.1 Due regard is to be paid to the design of the
1.1 The cross sectional area of a bar stem below aft body, rudder and propeller well in order to mini-
the load waterline is not to be less than: mize the forces excited by the propeller.
Ab = 1, 25 L [cm 2 ]
new C.1.1

new B.1 1.2 The following value is recommended for the

propeller clearance d0,9 related to 0,9 R (see Fig. 13.1).
1.2 Starting from the load waterline, the sectional
area of the bar stem may be reduced towards the upper  z 
end to 0,75 Ab. v0 (1 − sin (0,75 γ) )  0,5 + B 
 xF 
d0,9 ≥ 0,004 ⋅ n ⋅ d3p [m]

new B.1 D

2. Plate stem and bulbous bows R = propeller radius

v0 = ship's speed, see Section 1, H.5. [kn]
2.1 The thickness is not to be less than:
n = number of propeller revolutions per minute
t = ( 0,6 + 0,4 aB ) ( 0,08 L + 6) k [mm] D = maximum displacement of ship [t]
t max = 25 k [mm] dp = propeller diameter [m]

The plate thickness shall not be less than the required γ = skew angle of the propeller [°], see Fig. 13.2
thickness according to Section 6, C.2. zB = height of wheelhouse deck above weather

new B.2.1.1 deck [m]

The extension ℓ of the stem plate from its trailing edge xF = distance of deckhouse front bulkhead from
aftwards shall not be smaller than: aft edge of stern [m], see Fig. 13.1

new C.1.2
ℓ = 70 ⋅ L [mm]

new B.2.1.2
Chapter 1 Section 13 C Stem and Sternframe Structures I - Part 1
Page 13–2 GL 2012

Where other sections than rectangular ones are used,

their section modulus is not to be less than that result-
ing from ℓ and b.

zB
xF

new C.2.1

2.2 The scantlings of propeller posts of welded

LWL construction are to be determined according to the
following formulae:

ℓ = 50 L [mm]
d0,9
0,9R

b = 36 L [mm]
t = 2, 4 L ⋅ k [mm]
Fig. 13.1 Propeller clearance d0,9

new C.2.2

t
X X

b
Fig. 13.3 Propeller post
g

Note
Fig. 13.2 Skew angle With single-screw ships having in the propeller region
above the propeller flaring frames of more than
1.3 For single screw ships, the lower part of the α = 75° the thickness of the shell should not be less
sternframe is to be extended forward by at least 3 than the thickness of the propeller stem. For α ≤ 75°
times the frame spacing from fore edge of the boss, for the thickness may be 0,8 t. In no case the thickness
all other ships by 2 times the frame spacing from after shall be less than the thickness of the side shell ac-
edge of the sternframe. cording to Section 6.

new C.1.3
This recommendation applies for that part of the shell
which is bounded by an assumed sphere the centre of
1.4 The stern tube is to be surrounded by the
which is located at the top of a propeller blade in the
floor plates or, when the ship's shape is too narrow, to
twelve o’clock position and the radius of which is
be stiffened by internal rings. Where no sole piece is
fitted, the internal rings may be dispensed with. 0,75 ⋅ propeller diameter.

new C.1.4 Sufficient stiffening should be arranged, e.g. by floors

at each frame and by longitudinal girders.
1.5 The plate thickness of sterns of welded con-
new C.2.2 Note
struction for twin screw vessels shall not be less than:

t = (0, 07 L + 5, 0) k [mm] 2.3 Where the cross sectional configuration is

deviating from Fig. 13.3 and for cast steel propeller
t max = 22 k [mm] posts the section modulus of the cross section related
to the longitudinal axis is not to be less than:

new C.1.5
Wx = 1, 2 ⋅ L1,5 ⋅ k [cm3 ]
2. Propeller post

2.1 The scantlings of rectangular, solid propeller
new C.2.3

posts are to be determined according to the following
formulae: 2.4 The wall thickness of the boss in the propel-
ler post in its finished condition is to be at least 60 per
ℓ = 1, 4 L + 90 [mm] cent of the breadth b of the propeller post according to
b = 1, 6 L + 15 [mm] 2.1.

new C.2.4
I - Part 1 Section 13 C Stem and Sternframe Structures Chapter 1
GL 2012 Page 13–3

2.5 The wall thickness of the boss in propeller Wz

posts of welded construction according to 2.2 shall not Wy =
3
be less than 0,9 the wall thickness of the boss accord-
ing to D.2.
new C.3.2

new C.2.5
3.4 The sectional area at the location x = ℓ50 is
not to be less than:
3. Sole piece
B1
As = k [mm 2 ]
3.1 The section modulus of the sole piece related 48
to the z-axis is not to be less than:

new C.3.3
B1 ⋅ x ⋅ k
Wz = [cm3 ] 3.5 The equivalent stress taking into account
80
bending and shear stresses at any location within the

new C.3.1 length ℓ50 is not to exceed:

B1 = see A. 115
σv = σ2b + 3τ2 = [N / mm 2 ]
k
For rudders with two supports the support force is
approximately B1 = CR/2, when the elasticity of the
B1 ⋅ x
sole piece is ignored. σb = [N / mm 2 ]
Wz
x = distance of the respective cross section from
the rudder axis [m] B1
τ = [N / mm 2 ]
xmin = 0,5 ⋅ ℓ 50 As

new C.3.4
xmax = ℓ50

ℓ50 = see Fig. 13.4 and Section 14, C.3.2 4. Rudder horn of semi spade rudders

new A.1 4.1 The distribution of the bending moment,

shear force and torsional moment is to be determined
according to the following formulae:

– bending moment: Mb = B1 ⋅ z [Nm]

A Section A - A
z Mbmax = B1 ⋅ d [Nm]

y y – shear force: Q = B1 [N]

z – torsional moment: MT = B1 ⋅ e(z) [Nm]

A

new C.4.1
x
50 For determining preliminary scantlings the flexibility
of the rudder horn may be ignored and the supporting
Fig. 13.4 Length ℓ50 of a sole piece force B1 be calculated according to the following
formula:
3.2 The section modulus Wz may be reduced by 15
per cent where a rudder post according to 3.1 is fitted. b
B1 = CR [N]
c

new C.3.1
b, c, d, e(z) and z see Fig. 13.5 and 13.6
3.3 The section modulus related to the y-axis is b results from the position of the centre of gravity of
not to be less than: the rudder area.
– where no rudder post or rudder axle is fitted
new A.1
Wz
Wy =
2
– where a rudder post or rudder axle is fitted
Chapter 1 Section 13 C Stem and Sternframe Structures I - Part 1
Page 13–4 GL 2012

D 4.4 The equivalent stress at any location (z) of

the rudder horn shall not exceed the following value:

D
120
1 B2 σv = σ 2b + 3 τ2 + τT2
( ) = [N / mm 2 ]
k

Mb
σb = [N / mm 2 ]

c
d
Wx

b
B1 M T ⋅ 103
τT = [N / mm 2 ]
2 ⋅ AT ⋅ t h
CR
AT = sectional area [mm2] enclosed by the rudder
horn at the location considered
th = thickness of the rudder horn plating [mm]

Fig. 13.5 Arrangement of bearings of a semi
new C.4.4

spade rudder
4.5 When determining the thickness of the rudder
horn plating the provisions of 4.2 – 4.4 are to be com-
B1 · d B1 B1 · e(z) plied with. The thickness is, however, not to be less
than:

t min = 2, 4 L ⋅ k [mm]
d

new C.4.5
z

e(z) Mb Q MT 4.6 The rudder horn plating is to be effectively

connected to the aft ship structure, e.g. by connecting
the plating to longitudinal girders, in order to achieve
Fig. 13.6 Loads on the rudder horn a proper transmission of forces, see Fig. 13.7.

new C.4.6
4.2 The section modulus of the rudder horn in
transverse direction related to the horizontal x-axis is
at any location z not to be less than:

Mb ⋅ k
Wx = [cm3 ]
67

new C.4.2

4.3 At no cross section of the rudder horn the

shear stress due to the shear force Q is to exceed the
value:

48
τ = [N / mm 2 ]
k
The shear stress is to be determined by the following
formula:
B1
τ = [N / mm 2 ] Fig. 13.7 Rudder horn integration into the aft
Ah ship structure

Ah = effective shear area of the rudder horn in 4.7 Transverse webs of the rudder horn are to be
y-direction [mm2] led into the hull up to the next deck in a sufficient

new C.4.3 number and shall be of adequate thickness.

new C.4.7
I - Part 1 Section 13 E Stem and Sternframe Structures Chapter 1
GL 2012 Page 13–5

4.8 Strengthened plate floors are to be fitted in – length of boss see the GL Rules for
line with the transverse webs in order to achieve a Machinery Installati-
sufficient connection with the hull. The thickness of ons (I-1-2), Section 4,
these plate floors is to be increased by 50 per cent D.5.2
above the Rule values as required by Section 8.

new C.4.8 – wall thickness of boss 0,25 d

new D.2
4.9 The centre line bulkhead (wash-bulkhead) in
the after peak is to be connected to the rudder horn.
3. Propeller brackets and shaft bossings of

new C.4.9
welded construction are to have the same strength as
solid ones according to 2.
4.10 Where the transition between rudder horn and
shell is curved, about 50 % of the required total sec-
new D.3
tion modulus of the rudder horn is to be formed by the
webs in a Section A – A located in the centre of the
transition zone, i.e. 0,7 r above the beginning of the 4. For propeller brackets consisting of one strut
transition zone. See Fig. 13.8. only a strength analysis according to E.1.2 and a vi-
bration analysis according to E.2. are to be carried out.

new C.4.10 Due consideration is to be given to fatigue strength
aspects.

new D.4
0,7r

A A E. Elastic Stern Tube

1. Strength analysis

When determining the scantlings of the stern tube in

Fig. 13.8 Transition between rudder horn and way of the connection with the hull, the following
shell stresses are to be proved:

new E.1

D. Propeller Brackets 1.1 Static load

Bending stresses caused by static weight loads are not

1. The strut axes should intersect in the axis of to exceed 0,35 ReH.
the propeller shaft as far as practicable. The struts are
to be extended through the shell plating and are to be

new E..1.1
attached in an efficient manner to the frames and plate
floors respectively. The construction in way of the
shell is to be carried out with special care. In case of 1.2 Dynamic load
welded connection, the struts are to have a weld flange
or a thickened part or are to be connected with the The pulsating load due to loss of one propeller blade is
shell plating in another suitable manner. For strength- to be determined assuming that the propeller revolu-
ening of the shell in way of struts and shaft bossings, tions are equal to 0,75 times the rated speed. The fol-
see Section 6, F. The requirements of Section 19, lowing permissible stresses are to be observed:
B.4.3 are to be observed.

new D.1 σdzul = 0,40 R eH for R eH = 235 [N / mm2 ]

= 0,35 R eH for R eH = 355 [N / mm2 ]

2. The scantlings of solid struts are to be deter-
mined as outlined below depending on shaft diameter d: The aforementioned permissible stresses are approxi-
– thickness 0,44 d mate values. Deviations may be permitted in special
cases taking into account fatigue strength aspects.
– cross-sectional area 0,44 d2
in propeller bracket
new E.1.2
Chapter 1 Section 13 E Stem and Sternframe Structures I - Part 1
Page 13–6 GL 2012

2. Vibration analysis
The bending natural frequency at rated speed of the
system comprising stern tube, propeller shaft and
propeller is not to be less than 1,5 times the rated
propeller revolutions. However, it is not to exceed
0,66 times the exciting frequency of the propeller
(number of propeller blades × rated propeller revolu-
tions) and is not to coincide with service conditions,
including the damage condition (loss of one propeller
blade).

new E.2
I - Part 1 Section 14 A Rudder and Manoeuvring Arrangement Chapter 1
GL 2012 Page 14–1

Section 14

Rudder and Manoeuvring Arrangement

A. General

new B.2

1. Manoeuvring arrangement Connections of rudder blade structure with solid parts

in forged or cast steel, which are used as rudder stock
1.1 Each ship is to be provided with a manoeu- housing, are to be suitably designed to avoid any ex-
vring arrangement which will guarantee sufficient cessive stress concentration at these areas.
manoeuvring capability.
new B.4

new A.1.1
2.3 The rudder stock is to be carried through the
1.2 The manoeuvring arrangement includes all hull either enclosed in a watertight trunk, or glands are
parts from the rudder and steering gear to the steering to be fitted above the deepest load waterline, to pre-
position necessary for steering the ship. vent water from entering the steering gear compart-
ment and the lubricant from being washed away from
the rudder carrier. If the top of the rudder trunk is
1.3 Rudder stock, rudder coupling, rudder bear-
below the deepest waterline two separate stuffing
ings and the rudder body are dealt with in this Section.
boxes are to be provided.

new A.1.2

new B.3
The steering gear is to comply with the GL Rules for
Machinery Installation (I-1-2), Section 14. Note

new A.2.3 The following measures are recommended in the GL

Technical Publication, Paper No. 05-1 "Recommenda-
tions for Preventive Measures to Avoid or Minimize
1.4 The steering gear compartment shall be read-
Rudder Cavitation", regarding:
ily accessible and, as far as practicable, separated from
the machinery space. (See also Chapter II/1, Reg. Profile selection:
29.13 of SOLAS 74.)
– Use the appropriate profile shape and thickness.

new Section 27, D.3
– Use profiles with a sufficiently small absolute
Note value of pressure coefficient for moderate an-
gles of attack (below 5°). The pressure distribu-
Concerning the use of non-magnetisable material in
tion around the profile should be possibly
the wheel house in way of a magnetic compass, the
smooth. The maximum thickness of such profiles
requirements of the national Administration con-
is usually located at more than 35 % behind the
cerned are to be observed.
leading edge.

new Section 16, A.1 Note
– Use a large profile nose radius for rudders
operating in propeller slips.
1.5 For ice-strengthening see Section 15.
– Computational Fluid Dynamic (CFD) analysis

new A.2.2 for rudder considering the propeller and ship
wake can be used.
2. Structural details
Rudder sole cavitation:
2.1 Effective means are to be provided for sup-
Round out the leading edge curve at rudder sole.
porting the weight of the rudder body without exces-
sive bearing pressure, e.g. by a rudder carrier attached
to the upper part of the rudder stock. The hull structure Propeller hub cavitation:
in way of the rudder carrier is to be suitably strength- Fit a nacelle (body of revolution) to the rudder at the
ened. level of the propeller hub. This nacelle functions as an
extension of the propeller hub.

new B.1

2.2 Suitable arrangements are to be provided to Cavitation at surface irregularities:

prevent the rudder from lifting. – Grind and polish all welds.
Chapter 1 Section 14 A Rudder and Manoeuvring Arrangement I - Part 1
Page 14–2 GL 2012

– Avoid changes of profile shape. Often rudders
new C.1

are built with local thickenings (bubbles) and
dents to ease fitting of the rudder shaft. Maxi- 4.2 In general materials having a yield strength
mum changes in profile shape should be kept to ReH of less than 200 N/mm2 and a tensile strength of
less than two percent of profile thickness. less than 400 N/mm2 or more than 900 N/mm2 shall
not be used for rudder stocks, pintles, keys and bolts.
Gap cavitation:
– Round out all edges of the part around the gap. The requirements of this Section are based on a mate-
rial's yield strength ReH of 235 N/mm2. If material is
– Gap size should be as small as possible. used having a ReH differing from 235 N/mm2, the
– Place gaps outside of the propeller slipstream. material factor kr is to be determined as follows:

new B.4 Note 0,75
 235 
kr =   for R eH > 235 [N / mm 2 ]
3. Size of rudder area  R eH 
In order to achieve sufficient manoeuvring capability
the size of the movable rudder area A is recommended 235
= for R eH ≤ 235 [N / mm 2 ]
to be not less than obtained from the following for- R eH
mula:
ReH is not to be taken greater than 0,7 · Rm or
1, 75 ⋅ L ⋅ T
A = c1 ⋅ c2 ⋅ c3 ⋅ c 4 [m 2 ] 450 N/mm2, whichever is less.
100
c1 = factor for the ship type:
new C.2
= 1,0 in general
4.3 Before significant reductions in rudder stock
= 0,9 for bulk carriers and tankers having a diameter due to the application of steels with ReH
displacement of more than 50 000 t exceeding 235 N/mm2 are accepted, GL may require
= 1,7 for tugs and trawlers the evaluation of the elastic rudder stock deflections.
Large deflections should be avoided in order to avoid
c2 = factor for the rudder type: excessive edge pressures in way of bearings.
= 1,0 in general
new C.3
= 0,9 for semi-spade rudders
4.4 The permissible stresses given in E.1. are
= 0,7 for high lift rudders
applicable for normal strength hull structural steel.
c3 = factor for the rudder profile: When higher tensile steels are used, higher values
may be used which will be fixed in each individual
= 1,0 for NACA-profiles and plate rudder case.
= 0,8 for hollow profiles and mixed profiles

new C.4
c4 = factor for the rudder arrangement:
5. Definitions
= 1,0 for rudders in the propeller jet
= 1,5 for rudders outside the propeller jet CR = rudder force [N]
For semi-spade rudders 50 % of the projected area of QR = rudder torque [Nm]
the rudder horn may be included into the rudder area A.
A = total movable area of the rudder [m2], meas-
Where more than one rudder is arranged the area of
ured at the mid-plane of the rudder
each rudder can be reduced by 20 %.
For nozzle rudders, A is not to be taken less
Estimating the rudder area A B.1. is to be observed. than 1,35 times the projected area of the noz-

new A.4 as Note zle.

At = A + area of a rudder horn, if any [m2]

4. Materials
Af = portion of rudder area located ahead of the
4.1 For materials for rudder stock, pintles, cou-
rudder stock axis [m2]
pling bolts etc. see Rules II – Materials and Welding,
Part 1 – Metallic Materials. Special material require- b = mean height of rudder area [m]
ments are to be observed for the ice class notations E3
and E4 as well as for the ice class notations PC7 – c = mean breadth of rudder area [m], see Fig.
PC1. 14.1
I - Part 1 Section 14 B Rudder and Manoeuvring Arrangement Chapter 1
GL 2012 Page 14–3

x2 C R = 132 ⋅ A ⋅ v 2 ⋅ κ1 ⋅ κ 2 ⋅ κ3 ⋅ κ t [N]

c v = v0 for ahead condition

= va for astern condition
κ1 = coefficient, depending on the aspect ratio Λ
= (Λ + 2)/3, where Λ need not be taken greater

b
A
than 2
Af κ2 = coefficient, depending on the type of the
rudder and the rudder profile according to
Table 14.1
x1
κ3 = coefficient, depending on the location of the
rudder
x1 + x 2 A
c= 2 b= = 0,8 for rudders outside the propeller jet
c
= 1,0 elsewhere, including also rudders within
Fig. 14.1 Rudder area geometry the propeller jet

Λ = aspect ratio of rudder area At = 1,15 for rudders aft of the propeller nozzle
Table 14.1 Coefficient κ2
b2
=
At
κ2
Profile /
v0 = ahead speed of ship [kn] as defined in Section type of rudder ahead astern
1, H.5.;
NACA-00 series
if this speed is less than 10 kn, v0 is to be 1,1 1,4
Göttingen profiles
taken as
flat side profiles 1,1 1,4
( v0 + 20 ) mixed profiles
1,21 1,4
vmin = [kn] (e. g. HSVA)
3
hollow profiles 1,35 1,4
va = astern speed of ship [kn]; if the astern speed
va is less than 0,4 ⋅ v0 or 6 kn, whichever is to be specially
considered;
less, determination of rudder force and torque high lift rudders 1,7 if not known:
for astern condition is not required. For 1,7
greater astern speeds special evaluation of
rudder force and torque as a function of the
rudder angle may be required. If no limita- κt = coefficient depending on the thrust coeffi-
tions for the rudder angle at astern condition cient CTh
is stipulated, the factor κ2 is not to be taken
less than given in Table 14.1 for astern condi- = 1,0 normally
tion. In special cases for thrust coefficients CTh > 1,0 de-
k = material factor according to Section 2, B.2. termination of κt according to the following formula
may be required:
For ships strengthened for navigation in ice Section
15, B.9 is to be observed. C R (CTh )
κt =

new A.3 CR (CTh = 1, 0)

new D.1.1

B. Rudder Force and Torque 1.2 The rudder torque is to be determined by the
following formula:
1. Rudder force and torque for normal rud- Q R = C R ⋅ r [Nm]
ders
r = c (α − k b ) [m]
1.1 The rudder force is to be determined accord-
ing to the following formula: α = 0,33 for ahead condition
Chapter 1 Section 14 C Rudder and Manoeuvring Arrangement I - Part 1
Page 14–4 GL 2012

= 0,66 for astern condition (general) 2.2 The resulting torque of each part may be
= 0,75 for astern condition (hollow profiles) taken as:

For parts of a rudder behind a fixed structure such as a Q R1 = C R1 ⋅ r1 [Nm]

rudder horn:
Q R2 = C R2 ⋅ r2 [Nm]
α = 0,25 for ahead condition
= 0,55 for astern condition r1 = c1 (α − k b1 ) [m]
For high lift rudders α is to be specially considered. If r2 = c2 (α − k b2 ) [m]
not known, α = 0,40 may be used for the ahead condi- A1f
tion k b1 =
A1
kb = balance factor as follows: A 2f
k b2 =
Af A2
=
A A1f, A2f see Fig. 14.2
= 0,08 for unbalanced rudders
A1
rmin = 0,1 ⋅ c [m] for ahead condition c1 =
b1

new D.1.2 A2
c2 =
1.3 Effects of the provided type of rudder/profile b2
on choice and operation of the steering gear are to be b1, b2 = mean heights of the partial rudder areas A1
observed. and A2, see Fig. 14.2

2. Rudder force and torque for rudder blades
new D.2.2

with cut-outs (semi-spade rudders)
2.3 The total rudder torque is to be determined
2.1 The total rudder force CR is to be calculated according to the following formulae:
according to 1.1. The pressure distribution over the QR = Q R1 + QR 2 [Nm] or
rudder area, upon which the determination of rudder
torque and rudder blade strength are to be based, is to Q R min = CR ⋅ r1,2 min [Nm]
be derived as follows:
0,1
The rudder area may be divided into two rectangular r1,2min = (c1 ⋅ A1 + c2 ⋅ A 2 ) [m]
or trapezoidal parts with areas A1 and A2, see Fig. A
14.2. The resulting force of each part may be taken as: for ahead condition
A1 The greater value is to be taken.
C R1 = CR [N]
A

new D.2.3
A2
C R2 = CR [N]
A

new D.2.1 C. Scantlings of the Rudder Stock

c1
1. Rudder stock diameter

1.1 The diameter of the rudder stock for transmit-

A1f ting the rudder torque is not to be less than:
A1
b1

Dt = 4, 2 3 QR ⋅ k r [mm]

QR = see B.1.2 and B.2.2 – B.2.3

A2 A2f
b2

The related torsional stress is:

68
τt = [N / mm 2 ]
c2 kr
kr = see A.4.2
Fig. 14.2 Partial rudder areas A1 and A2
I - Part 1 Section 14 C Rudder and Manoeuvring Arrangement Chapter 1
GL 2012 Page 14–5

new E.1.1 2
61+
4  Mb 
D1 = 0,1 ⋅ D t  
1.2 The steering gear is to be determined accord- 3  QR 
ing to the GL Rules for Machinery Installations (I-1-
2), Section 14 for the rudder torque QR as required in QR = see B.1.2 and B.2.2 – B.2.3
B.1.2, B.2.2 or B.2.3 and under consideration of the
frictional losses at the rudder bearings. Dt = see 1.1

new E.2.1
1.3 In case of mechanical steering gear the di-
ameter of the rudder stock in its upper part which is Note
only intended for transmission of the torsional mo-
ment from the auxiliary steering gear may be 0,9 Dt. Where a double-piston steering gear is fitted, addi-
The length of the edge of the quadrangle for the auxil- tional bending moments may be transmitted from the
iary tiller shall not be less than 0,77 Dt and the height steering gear into the rudder stock. These additional
bending moments are to be taken into account for
not less than 0,8 Dt.
determining the rudder stock diameter.

new E.1.2
new E.2.1 Note

1.4 The rudder stock is to be secured against 3. Analysis

axial sliding. The degree of the permissible axial
clearance depends on the construction of the steering 3.1 General
engine and on the bearing.
The evaluation of bending moments, shear forces and

new E.1.3 support forces for the system rudder - rudder stock
may be carried out for some basic rudder types as
shown in Figs. 14.3 – 14.5 as outlined in 3.2 – 3.3.
2. Strengthening of rudder stock

new E.3.1
2.1 If the rudder is so arranged that additional
3.2 Data for the analysis
bending stresses occur in the rudder stock, the stock
diameter has to be suitably increased. The increased
diameter is, where applicable, decisive for the scant- ℓ10 – ℓ40 = lengths of the individual girders of the
lings of the coupling. system [m]

For the increased rudder stock diameter the equivalent I10 – I40 = moments of inertia of these girders [cm4]
stress of bending and torsion is not to exceed the fol-
lowing value: For rudders supported by a sole piece the length ℓ20 is
the distance between lower edge of rudder body and
centre of sole piece, and I20 is the moment of inertia of
118
σv = σb2 + 3τ2 ≤ [N / mm 2 ] the pintle in the sole piece.
kr
Load on rudder body (general):

Bending stress: CR
pR = [kN / m]
ℓ10 ⋅ 103
10, 2 ⋅ M b
σb = [N / mm 2 ] Load on semi-spade rudders:
D13
CR 2
p R10 = [kN / m]
Mb = bending moment at the neck bearing [Nm] ℓ10 ⋅ 103

CR1
Torsional stress: p R 20 = [kN / m]
ℓ 20 ⋅ 103
5,1 ⋅ Q R
τ = [N / mm 2 ] CR, CR1, CR2 see B.1. and B.2.
D13
Z = spring constant of support in the sole piece or
D1 = increased rudder stock diameter [cm] rudder horn respectively
for the support in the sole piece (Fig. 14.3):
The increased rudder stock diameter may be deter-
mined by the following formula:
Chapter 1 Section 14 C Rudder and Manoeuvring Arrangement I - Part 1
Page 14–6 GL 2012

6,18 ⋅ I50 d ⋅ e2 ⋅ Σ ui ti
Z = [kN / m] = [m / kN] for steel
3
ℓ 50 3,17 ⋅ 108 ⋅ FT2
for the support in the rudder horn (Fig. 14.4): G = modulus of rigity
1
Z = [kN / m]
fb + ft = 7,92 ⋅ 107 [kN/m2] for steel

fb = unit displacement of rudder horn [m] due to a Jt = torsional moment of inertia [m4]
unit force of 1 kN acting in the centre of sup-
port FT = mean sectional area of rudder horn [m2]
d3
= 0, 21 [m / kN] (guidance value for steel) ui = breadth [mm] of the individual plates forming
In
the mean horn sectional area
In = moment of inertia of rudder horn [cm4]
around the x-axis at d/2 (see also Fig. 14.4) ti = plate thickness within the individual breadth
ui [mm]
ft = unit displacement due to a torsional moment
of the amount 1 ⋅ e [kNm] e, d = distances [m] according to Fig. 14.4
2
d ⋅ e
=
new E.3.2
G ⋅ Jt

B3

Mb
40

I40 B2
30

I30
10

I10 pR MR
20 I20

I50
Z

B1
50 System M Q

Fig. 14.3 Rudder supported by sole piece

I - Part 1 Section 14 C Rudder and Manoeuvring Arrangement Chapter 1
GL 2012 Page 14–7

B3

I40

40
Mb B2

30
I 30

20
I20 B1

d
pR20 Q1
d
2
Z

e
I10 10

pR10

System M Q

Fig. 14.4 Semi-spade rudder

Chapter 1 Section 14 C Rudder and Manoeuvring Arrangement I - Part 1
Page 14–8 GL 2012

B3

30
B2

20
x2
10 Mb

pR

x1 System M Q

Fig. 14.5 Spade rudder

B3

30 Mb
x3
B2
MCR1
20 A1
Z= 10
CR1
x2
MR
10
pR
A2

Z=0
x1 System M Q

Fig. 14.6 Spade rudders with rudder trunks inside the rudder body

3.3 Moments and forces to be evaluated

 ℓ (2 x1 + x 2 ) 
3.3.1 The bending moment MR and the shear force M b = CR  ℓ 20 + 10  [Nm]
 3 (x1 + x 2 ) 
Q1 in the rudder body, the bending moment Mb in the
neck bearing and the support forces B1, B2, B3 are to Mb
B3 = [N]
be evaluated. ℓ 30
The so evaluated moments and forces are to be used
for the stress analyses required by 2. and E.1. of this B2 = CR + B3 [N]
Section and by Section 13, C.4. and C.5.
new E.3.3.2

new E.3.3.1
3.3.3 For spade rudders with rudder trunks (see
3.3.2 For spade rudders the moments and forces Fig. 14.6) the moments and forces may be determined
may be determined by the following formulae: by the following formulae:
I - Part 1 Section 14 D Rudder and Manoeuvring Arrangement Chapter 1
GL 2012 Page 14–9

CR1 = rudder force over the partial rudder area A1 4.4 Alternatively a fatigue strength calculation
according to B.2.1 [N] based on the structural stress (hot spot stress) (see Sec-
tion 20, A.2.6) can be carried out.
CR2 = rudder force over the partial rudder area A2
according to B.2.1 [N]
new E.4.4

4.4.1 In case the rudder trunk is welded directly

 2 x2 + x3 
MCR1 = C R1 ⋅ ℓ 20 1 −  [Nm] into the skeg bottom or shell, hot spot stress has to be
 3(x 2 + x 3 )  determined acc. to Section 20, C.

ℓ10 (2 x1 + x 2 ) In this case FAT class ∆σR = 100 has to be used, see
MCR2 = C R 2 ⋅ [Nm] Section 20, C.3.
3 (x1 + x 2 )

new E.4.4.1
MR = Max (MCR1, MCR2) [Nm]
4.4.2 In case the trunk is fitted with a weld flange,
Mb = MCR2 – MCR1 the stresses have to be determined within the radius.
FAT class ∆σR for the case E 2 or E 3 acc. to Section
Mb 20, Table 20.3 has to be used. In addition sufficient
B3 = [N] fatigue strength of the weld has to be verified e.g. by a
ℓ 20 + ℓ 30
calculation acc. to 4.4.1.
B2 = CR + B 3 [N]
new E.4.4.2

new E.3.3.3
Note
4. Rudder trunk The radius may be obtained by grinding. If disk grind-
ing is carried out, score marks are to be avoided in
4.1 In case where the rudder stock is fitted with a the direction of the weld.
rudder trunk welded in such a way the rudder trunk is The radius is to be checked with a template for accu-
loaded by the pressure induced on the rudder blade, as racy. Four profiles at least are to be checked. A report
given in B.1.1, the bending stress in the rudder trunk, is to be submitted to the Surveyor.
in N/mm2, is to be in compliance with the following
formula:
new E.4.4.2 Note
Before welding is started, a detailed welding proce-
σ ≤ 80 / k
dure specification is to be submitted to GL covering
where the material factor k for the rudder trunk is not the weld preparation, welding positions, welding pa-
to be taken less than 0,7. rameters, welding consumables, preheating, post weld
heat treatment and inspection procedures. This weld-
For the calculation of the bending stress, the span to ing procedure is to be supported by approval tests in
be considered is the distance between the mid-height accordance with the applicable requirements of mate-
of the lower rudder stock bearing and the point where rials and welding sections of the rules.
the trunk is clamped into the shell or the bottom of the
skeg. The manufacturer is to maintain records of welding,
subsequent heat treatment and inspections traceable

new E.4.1 to the welds. These records are to be submitted to the
Surveyor.
4.2 The weld at the connection between the rud-
Non destructive tests are to be conducted at least 24
der trunk and the shell or the bottom of the skeg is to
hours after completion of the welding. The welds are
be full penetration.
to be 100 % magnetic particle tested and 100 % ultra-
Non destructive tests are to be conducted for all welds. sonic tested.

new E.4.2
ItS

4.3 The minimum thickness of the shell or the

bottom of the skeg is to be 0,4 times the wall thickness
of the trunk at the connection. D. Rudder Couplings

The fillet shoulder radius is to be ground. The radius is 1. General

to be as large as practicable but not less than 0,7 times
the wall thickness of the trunk at the connection, if the 1.1 The couplings are to be designed in such a
wall thickness is greater than 50 mm. In case of smaller way as to enable them to transmit the full torque of the
wall thickness, the radius shall be not less than 35 mm. rudder stock.

new E.4.3
new F.1.1
Chapter 1 Section 14 D Rudder and Manoeuvring Arrangement I - Part 1
Page 14–10 GL 2012

1.2 The distance of the bolt axis from the edges kr = material factor for the rudder stock as given
of the flange is not to be less than 1,2 times the diame- in A.4.2
ter of the bolt. In horizontal couplings, at least 2 bolts
are to be arranged forward of the stock axis. kb = material factor for the bolts analogue to A.4.2

new F.1.2
new F.2.1

1.3 The coupling bolts are to be fitted bolts. The 2.2 The thickness of the coupling flanges is not
bolts and nuts are to be effectively secured against to be less than determined by the following formulae:
loosening.

new F.1.3 D3 ⋅ k f
tf = 0, 62 [mm]
kr ⋅ n ⋅ e
1.4 For spade rudders horizontal couplings ac-
cording to 2. are permissible only where the required tfmin = 0,9 ⋅ db
thickness of the coupling flanges tf is less than 50 mm,
otherwise cone couplings according to 3. are to be kf = material factor for the coupling flanges ana-
applied. For spade rudders of the high lift type, only logue to A.4.2
cone couplings according to 3. are permitted. The thickness of the coupling flanges clear of the bolt

new F.1.4 holes is not to be less than 0,65 ⋅ tf.

1.5 If a cone coupling is used between the rudder The width of material outside the bolt holes is not to
stock or pintle, as the case can be, and the rudder blade be less than 0,67 ⋅ db.
or steering gear (see 3.), the contact area between the
new F.2.2
mating surfaces is to be demonstrated to the Surveyor
by blue print test and should not be less than 70 % of 2.3 The coupling flanges are to be equipped with
the theoretical contact area (100 %). Non-contact a fitted key according to DIN 6885 or equivalent stan-
areas should be distributed widely over the theoretical dard for relieving the bolts.
contact area. Concentrated areas of non-contact in the
forward regions of the cone are especially to be The fitted key may be dispensed with if the diameter
avoided. The proof has to be demonstrated using the of the bolts is increased by 10 %.
original components and the assembling of the com-

new F.2.3
ponents has to be done in due time to the creation of
blue print to ensure the quality of the surfaces. In case
of storing over a longer period, sufficient preservation 2.4 Horizontal coupling flanges shall either be
of the surfaces is to be provided for. forged together with the rudder stock or be welded to
the rudder stock as outlined in Section 19, B.4.4.3.
If alternatively a male/female calibre system is used,
the contact area between the mating surfaces is to be
new F.2.4
checked by blue print test and should not be less than
80 % of the theoretical contact area (100 %) and needs 2.5 For the connection of the coupling flanges
to be certified. After ten applications or five years the with the rudder body see also Section 19, B.4.4.
blue print proof has to be renewed.
new F.2.4

new F.1.5
3. Cone couplings
2. Horizontal couplings
3.1 Cone couplings with key
2.1 The diameter of coupling bolts is not to be
3.1.1 Cone couplings shall have a taper c on diameter
less than:
of 1 : 8 - 1 : 12. c = (d0 – du)/ℓ according to Fig. 14.7.

D3 ⋅ k b The cone shapes should fit very exact. The nut is to be

db = 0, 62 [mm] carefully secured, e.g. by a securing plate as shown in
kr ⋅ n ⋅ e Fig. 14.7.

D = rudder stock diameter according to C. [mm]
new F.3.1.1

n = total number of bolts, which is not to be less 3.1.2 The coupling length ℓ shall, in general, not be
than 6 less than 1,5 ⋅ d0.
e = mean distance of the bolt axes from the cen-
new F.3.1.1
tre of bolt system [mm]
I - Part 1 Section 14 D Rudder and Manoeuvring Arrangement Chapter 1
GL 2012 Page 14–11

3.1.3 For couplings between stock and rudder a key dg = 0,65 ⋅ d0

is to be provided, the shear area of which is not to be
less than:
new F.3.1.4

16 ⋅ Q F 3.1.6 It is to be proved that 50 % of the design yield

as = [cm 2 ] moment will be solely transmitted by friction in the
d k ⋅ R eH1
cone couplings. This can be done by calculating the
QF = design yield moment of rudder stock [Nm] required push-up pressure and push-up length accord-
according to F. ing to 3.2.3 for a torsional moment Q'F = 0,5 ⋅ QF.
dk = diameter of the conical part of the rudder
new F.3.1.5
stock [mm] at the key
3.2 Cone couplings with special arrangements
ReH1 = yield strength of the key material [N/mm2] for mounting and dismounting the couplings

new F.3.1.2
3.2.1 Where the stock diameter exceeds 200 mm
the press fit is recommended to be effected by a hy-
d0 draulic pressure connection. In such cases the cone
insulation
shall be more slender, c ≈ 1 : 12 to ≈ 1 : 20.
liner
new F.3.2.1
sealing/
3.2.2 In case of hydraulic pressure connections the
insulation
nut is to be effectively secured against the rudder stock
or the pintle. A securing plate for securing the nut against
da the rudder body is not to be provided, see Fig. 14.8.

new F.3.2.2
dm

du
hn

dg
securing
dn plate for nut

Fig. 14.7 Cone coupling with key and securing

plate

3.1.4 The effective surface area of the key (without

rounded edges) between key and rudder stock or cone dg
coupling is not to be less than: Securing
flat bar d1
5 ⋅ QF 2
ak = [cm ]
d k ⋅ R eH2 Fig. 14.8 Cone coupling without key and with
securing flat bar
ReH2 = yield strength of the key, stock or coupling
material [N/mm2], whichever is less. Note

new F.3.1.3 A securing flat bar will be regarded as an effective
securing device of the nut, if its shear area is not less
3.1.5 The dimensions of the slugging nut are to be than:
at least as follows, see Fig. 14.7:
Ps ⋅ 3
– height: As = [ mm 2 ]
ReH
hn = 0,6 ⋅ dg
Ps = shear force as follows
– outer diameter (the greater value to be taken):
Pe d 
dn = 1,2 ⋅ du or dn = 1,5 ⋅ dg = ⋅ µ1  1 − 0,6  [N]
2  dg 
 
– external thread diameter:
Chapter 1 Section 14 E Rudder and Manoeuvring Arrangement I - Part 1
Page 14–12 GL 2012

Pe = push-up force according to 3.2.3.2 [N] 3.2.3.2 Push-up length

µ1 = frictional coefficient between nut and rudder The push-up length is not to be less than:
body, normally µ1 = 0,3 preq ⋅ dm 0,8 ⋅ R tm
∆ℓ1 = + [mm]
d1 = mean diameter of the frictional area between 1 − α 2 c
E
 2 
nut and rudder body, see Fig. 14.8 c
 
dg = thread diameter of the nut

new F.3.2.3 as requirement Rtm = mean roughness [mm]
≈ 0,01 mm
3.2.3 For the safe transmission of the torsional
moment by the coupling between rudder stock and c = taper on diameter according to 3.2.1
rudder body the push-up length and the push-up pres- The push-up length is, however, not to be taken
sure are to be determined by the following formulae. greater than:

new F.3.2.4
1,6 ⋅ R eH ⋅ d m 0,8 ⋅ R tm
∆ℓ 2 = + [mm]
3.2.3.1 Push-up pressure 3 + α 4
E ⋅ c c
The push-up pressure is not to be less than the greater
of the two following values:
new F.3.2.4.2

2 ⋅ QF ⋅ 103 Note
p req1 = [N / mm 2 ]
d 2m ⋅ ℓ ⋅ π ⋅ µ0 In case of hydraulic pressure connections the required
push-up force Pe for the cone may be determined by
the following formula:
6 ⋅ M b ⋅ 103
p req2 = [N / mm 2 ]
ℓ 2 ⋅ dm c 
Pe = preq ⋅ d m ⋅ π ⋅ ℓ  + 0,02  [N]
2 
QF = design yield moment of rudder stock accord- The value 0,02 is a reference for the friction coefficient
ing to F. [Nm] using oil pressure. It varies and depends on the mecha-
dm = mean cone diameter [mm] nical treatment and roughness of the details to be fixed.
Where due to the fitting procedure a partial push-up
ℓ = cone length [mm] effect caused by the rudder weight is given, this may
be taken into account when fixing the required push-
µ0 ≈ 0,15 (frictional coefficient) up length, subject to approval by GL.
Mb = bending moment in the cone coupling (e.g. in
new F.3.2.4.2 Note
case of spade rudders) [Nm]
3.2.4 The required push-up pressure for pintle bear-
It has to be proved that the push-up pressure does not ings is to be determined by the following formula:
exceed the permissible surface pressure in the cone.
The permissible surface pressure is to be determined B1 ⋅ d0
by the following formula: p req = 0, 4 [N / mm 2 ]
d 2m ⋅ ℓ
0,8 ⋅ R eH (1 − α 2 ) B1 = supporting force in the pintle bearing [N], see
p perm =
3+α 4 also Fig. 14.4
dm, ℓ = see 3.2.3
ReH = yield strength [N/mm2] of the material of the
gudgeon d0 = pintle diameter [mm] according to Fig. 14.7
dm
new G.5.4
α = (see Fig. 14.7)
da

The outer diameter of the gudgeon shall not be less than: E. Rudder Body, Rudder Bearings
da = 1,5 ⋅ d m [mm]
1. Strength of rudder body

new F.3.2.4.1
1.1 The rudder body is to be stiffened by hori-
zontal and vertical webs in such a manner that the
I - Part 1 Section 14 E Rudder and Manoeuvring Arrangement Chapter 1
GL 2012 Page 14–13

rudder body will be effective as a beam. The rudder A-B

shall be additionally stiffened at the aft edge.

new G.1.1 2 2

r
a a

f2
1.2 The strength of the rudder body is to be

t
f1
proved by direct calculation according to C.3.

r
x x

h
A A2 B

new G.1.2
a
1.3 For rudder bodies without cut-outs the per- a e
missible stress are limited to:
bending stress due to MR: Fig. 14.9 Geometry of a semi-spade rudder

σb = 110 N / mm 2 The torsional stress may be calculated in a simplified

manner as follows:
shear stress due to Q1:
Mt
τ = 50 N / mm 2 τt = [N / mm 2 ]
2 ⋅ ℓ ⋅ h ⋅ t
equivalent stress due to bending and shear:
Mt = C R2 ⋅ e [Nm]
σv = σ2b + 3τ2 = 120 N / mm 2 CR2 = partial rudder force [N] of the partial rudder
area A2 below the cross section under consid-
MR, Q1 see C.3.3 and Fig. 14.3 and 14.4.
eration

new G.1.3
e = lever for torsional moment [m]
In case of openings in the rudder plating for access to (horizontal distance between the centre of
cone coupling or pintle nut the permissible stresses pressure of area A2 and the centre line a-a of
according to 1.4 apply. Smaller permissible stress the effective cross sectional area under con-
values may be required if the corner radii are less than sideration, see Fig. 14.9. The centre of pres-
0,15 ⋅ ho, where ho = height of opening. sure is to be assumed at 0,33 ⋅ c2 aft of the

new G.1.4 forward edge of area A2, where c2 = mean
breadth of area A2).
1.4 In rudder bodies with cut-outs (semi-spade
rudders) the following stress values are not to be ex- h, ℓ, t = [cm], see Fig. 14.9
ceeded:
bending stress due to MR: The distance ℓ between the vertical webs shall not
exceed 1,2 ⋅ h.
σb = 90 N / mm 2 The radii in the rudder plating are not to be less than
4 – 5 times the plate thickness, but in no case less than
shear stress due to Q1: 50 mm.
τ = 50 N / mm 2
new G.1.5
torsional stress due to Mt: 2. Rudder plating
2
τt = 50 N / mm 2.1 The thickness of the rudder plating is to be
determined according to the following formula:
equivalent stress due to bending and shear and equiva-
lent stress due to bending and torsion:
t = 1, 74 ⋅ a pR ⋅ k + 2,5 [mm]
σ v1 = σ2b + 3τ 2
= 120 N / mm 2
CR
pR = 10 ⋅ T + [kN / m 2 ]
3
σ v2 = σb2 + 3τt2 = 100 N / mm 2 10 ⋅ A

f2 a = the smaller unsupported width of a plate

M R = C R2 ⋅ f1 + B1 [Nm] panel [m]
2
The influence of the aspect ratio of the plate panels
Q1 = CR2 [N]
may be taken into account as given in Section 3, A.3.
f1, f2 = see Fig. 14.9 The thickness shall, however, not be less than the
thickness tmin according to Section 6, B.3.1.
Chapter 1 Section 14 E Rudder and Manoeuvring Arrangement I - Part 1
Page 14–14 GL 2012

new G.2.1
new G.4.2

To avoid resonant vibration of single plate fields the 4.3 The bearing forces result from the direct calcu-
frequency criterion as defined in Section 12, A.8.3 for lation mentioned in C.3. As a first approximation the
shell structures applies analogously. bearing force may be determined without taking account

new G.2.2 of the elastic supports. This can be done as follows:

Regarding dimensions and welding Section 19, B.4.4.1 – normal rudder with two supports:
has to be observed in addition. The rudder force CR is to be distributed to the

new G.2.3 supports according to their vertical distances
from the centre of gravity of the rudder area.
2.2 For connecting the side plating of the rudder – semi-spade rudders:
to the webs tenon welding is not to be used. Where
– support force in the rudder horn:
application of fillet welding is not practicable, the side
plating is to be connected by means of slot welding to b
B1 = CR ⋅ [N]
flat bars which are welded to the webs. c

new G.2.4 – support force in the neck bearing:
B2 = CR − B1 [N]
2.3 The thickness of the webs is not to be less
than 70 % of the thickness of the rudder plating ac- For b and c see Fig. 13.5 in Section 13.
cording to 2.1, but not less than:

new G.4.3
t min = 8 k [mm]
4.4 The projected bearing surface Ab (bearing
Webs exposed to seawater shall be dimensioned ac-
cording to 2.1. height × external diameter of liner) is not to be less
than

new G.2.5
B
Ab = [mm 2 ]
q
3. Transmitting of the rudder torque
B = support force [N]
3.1 For transmitting the rudder torque, the rudder
plating according to 2.1 is to be increased by 25 % in q = permissible surface pressure acc. to Table 14.2
way of the coupling. A sufficient number of vertical
new G.4.4
webs is to be fitted in way of the coupling.

new G.3.1 Table 14.2 Permissible surface pressure q
3.2 If the torque is transmitted by a prolonged
shaft extended into the rudder, the latter shall have the Bearing material q [N/mm2]
diameter Dt or D1, whichever is greater, at the upper
lignum vitae 2,5
10 % of the intersection length. Downwards it may be
tapered to 0,6 Dt, in spade rudders to 0,4 times the white metal, oil lubricated 4,5
strengthened diameter, if sufficient support is provided
for. synthetic material 1 5,5

new G.3.2 steel 2,

bronze and hot-pressed
7,0
bronze-graphite materials
4. Rudder bearings 1 Synthetic materials to be of approved type.
Surface pressures exceeding 5,5 N/mm 2 may be accepted
4.1 In way of bearings liners and bushes are to be in accordance with bearing manufacturer's specification
fitted. Their minimum thickness is and tests, but in no case more than 10 N/mm 2.
tmin = 8 mm for metallic materials and 2 Stainless and wear resistant steel in an approved combi-
nation with stock liner. Higher surface pressures than
synthetic material
7 N/mm 2 may be accepted if verified by tests.
= 22 mm for lignum material
Where in case of small ships bushes are not fitted, the rud- 4.5 Stainless and wear resistant steels, bronze and
der stock is to be suitably increased in diameter in way of hot-pressed bronze-graphit materials have a consider-
bearings enabling the stock to be re-machined later. able difference in potential to non-alloyed steel. Re-

new G.4.1 spective preventive measures are required.

new G.4.5
4.2 An adequate lubrication is to be provided.
I - Part 1 Section 14 G Rudder and Manoeuvring Arrangement Chapter 1
GL 2012 Page 14–15

4.6 The bearing height shall be equal to the bear-
new G.6.1
ing diameter, however, is not to exceed 1,2 times the
bearing diameter. Where the bearing depth is less than 6.2 If non-metallic bearing material is applied,
the bearing diameter, higher specific surface pressures the bearing clearance is to be specially determined
may be allowed. considering the material's swelling and thermal expan-

new G.4.6 sion properties.

new G.6.2
4.7 The wall thickness of pintle bearings in sole
piece and rudder horn shall be approximately ¼ of the 6.3 The clearance is not to be taken less than
pintle diameter. 1,5 mm on diameter. In case of self lubricating bushes
going down below this value can be agreed to on the

new G.4.7
basis of the manufacturer's specification.

5. Pintles
new G.6.3

5.1 Pintles are to have scantlings complying with

the conditions given in 4.4 and 4.6. The pintle diame-
F. Design Yield Moment of Rudder Stock
ter is not to be less than:
The design yield moment of the rudder stock is to be
d = 0,35 B1 ⋅ k r [mm] determined by the following formula:

B1 = support force [N] D3t

Q F = 0, 02664 [Nm]
kr = see A.4.2 kr
Dt = stock diameter [mm] according to C.1.

new G.5.1
Where the actual diameter Dta is greater than the calcu-
5.2 The thickness of any liner or bush shall not
lated diameter Dt, the diameter Dta is to be used. How-
be less than:
ever, Dta need not be taken greater than 1,145 ⋅ Dt.
t = 0, 01 B1 [mm]
new H
or the values in 4.1 respectively.

new G.5.2
G. Stopper, Locking Device
5.3 Where pintles are of conical shape, they are
to comply with the following 1. Stopper
taper on diameter 1 : 8 to 1 : 12 The motions of quadrants or tillers are to be limited on
if keyed by slugging nut either side by stoppers. The stoppers and their founda-
taper on diameter 1 : 12 to 1 : 20 tions connected to the ship's hull are to be of strong
if mounted with oil injec- construction so that the yield strength of the applied
tion and hydraulic nut materials is not exceeded at the design yield moment
of the rudder stock.

new G.5.3

new I.1
5.4 The pintles are to be arranged in such a manner
as to prevent unintentional loosening and falling out. 2. Locking device
For nuts and threads the requirements of D.3.1.5 and Each steering gear is to be provided with a locking
3.2.2 apply accordingly. device in order to keep the rudder fixed at any posi-

new G.5.5 tion. This device as well as the foundation in the ship's
hull are to be of strong construction so that the yield
strength of the applied materials is not exceeded at the
6. Guidance values for bearing clearances design yield moment of the rudder stock as specified
in F. Where the ship's speed exceeds 12 kn, the design
6.1 For metallic bearing material the bearing yield moment need only be calculated for a stock
clearance shall generally not be less than: diameter based on a speed v0 = 12 kn.
db
new I.2
+ 1, 0 [mm]
1000
db = inner diameter of bush
Chapter 1 Section 14 I Rudder and Manoeuvring Arrangement I - Part 1
Page 14–16 GL 2012

3. Regarding stopper and locking device see also b

the GL Rules for Machinery Installations (I-1-2), Sec-
tion 14. zone 4

new I.3

H. Propeller Nozzles zone 3 zone 2 zone 1

min. b/4
1. General Fig. 14.10 Zones 1 to 4 of a propeller nozzle
1.1 The following requirements are applicable to
propeller nozzles having an inner diameter of up to 3. Plate thickness
5 m. Nozzles with larger diameters will be specially
considered. 3.1 The thickness of the nozzle shell plating is

new J.1.1 not to be less than:

1.2 Special attention is to be given to the support t = 5 ⋅ a pd + t K [mm]

of fixed nozzles at the hull structure.
t min = 7,5 mm

new J.1.2
a = spacing of ring stiffeners [m]
2. Design pressure
new J.3.1
The design pressure for propeller nozzles is to be
determined by the following formula: 3.2 The web thickness of the internal stiffening
rings shall not be less than the nozzle plating for zone
pd = c ⋅ pd0 [kN / m 2 ] 3, however, in no case be less than 7,5 mm.

N
new J.3.2
pd0 = ε [kN / m 2 ]
Ap
4. Section modulus
N = maximum shaft power [kW] The section modulus of the cross section shown in
Ap = propeller disc area [m2] Fig. 14.10 around its neutral axis is not to be less
than:
π
= D2 W = n ⋅ d 2 ⋅ b ⋅ v 02 [cm3 ]
4
D = propeller diameter [m] d = inner diameter of nozzle [m]

ε = factor according to the following formula: b = length of nozzle [m]

n = 1,0 for rudder nozzles
N
ε = 0, 21 − 2 ⋅ 10−4 = 0,7 for fixed nozzles
Ap
εmin = 0,10
new J.4

c = 1,0 in zone 2 (propeller zone) 5. Welding

= 0,5 in zones 1 and 3 The inner and outer nozzle shell plating is to be
welded to the internal stiffening rings as far as practi-
= 0,35 in zone 4 cable by double continuous welds. Plug welding is
see Fig. 14.10 only permissible for the outer nozzle plating.

new J.2
new J.5
I. Devices for Improving Propulsion Efficiency

1. The operation of the ship and the safety of the

hull, propeller and the rudder are not to be affected by
damage, loss or removal of additional devices that
improve the propulsion efficiency (e.g. spoilers, fins
or ducts).

new K.1
I - Part 1 Section 14 J Rudder and Manoeuvring Arrangement Chapter 1
GL 2012 Page 14–17

2. Integration into the hull structure

2. Documentation of strength and vibration analy-
ses are to be submitted for devices of innovative design. 2.1 The complete bearing system and the drive
In addition sufficient fatigue strength of the connection unit directly mounted at the fin stock are to be located
with the ship's structure has to be verified. The scant- within an own watertight compartment at the ship's
lings of the devices are to be in compliance with the side or bottom of moderate size. For further details
required ice class, where applicable. The relevant load refer to the GL Rules for Machinery Installations (I-1-
cases are to be agreed upon with GL. 2), Section 14, H.

new K.2
new L.2.1

2.2 At the penetration of the fin stock and at the

slot of retractable fins, the shell has to be strengthened
J. Fin Stabilizers in a sufficient way.
1. General
new L.2.2
The hydrodynamic effects of fin stabilizers on the 2.3 The watertight boundaries of the fin recess,
rolling behaviour of the ship are not part of the classi- if applicable and of the drive compartment have to
fication procedure. The classification however in- be dimensioned according to Section 6. Special atten-
cludes the integration of the system into the hull struc- tion has to be given to the transmission of the fin sup-
ture. port forces from the stock bearings into the ships

new L.1 structure.

new L.2.3
I - Part 1 Section 15 A Strengthening for Navigation in Ice Chapter 1
GL 2012 Page 15–1

Section 15

Strengthening for Navigation in Ice

A. General the same as those for ice class notations E2 and E1,
respectively, except for the calculation of minimum pro-

in this Section only changes in numbering in A.3 pulsion machinery output, see A.3. When calculating the
resistance of the vessel, the thickness of brash ice in mid
1. Ice class notations channel, HM, is to be taken as 0,65 m for ice class nota-
tion IBV and 0,50 m for ice class notation ICV. For
1.1 The strengthenings for the various ice class vessels complying with the requirements for ice class
notations are recommended for navigation under the notations IBV and ICV, a corresponding entry will be
following ice conditions: made in the Technical File to the Class Certificate.

Ice class 1.4 The ice class notations E1 – E4 can only be

notation Ice conditions assigned to self-propelled ships when in addition to
the requirements of this Section also the relevant GL
Drift ice in mouths of rivers Construction Rules for Machinery Installations (I-1-
E
and coastal regions
2), Section 13 are complied with. For example, the full
E1 Character of Classification then reads:  100A5 E1
E2 Ice conditions as in the MC E1. Where the hull only is strengthened for a
E3 Northern Baltic 1 higher ice class notation, a corresponding entry will be
made in the Technical File to the Class Certificate.
E4
1 See paragra ph 1.1 of the Finnish-Swedish Ice Class Rules 1.5 Ships the ice-strengthening of which com-
plies with the requirements of C. will have the nota-
tion E affixed to their Character of Classification.
1.2 Ships the ice-strengthening of which com-
plies with the requirements of B. will have the nota- Upon request, the notation E may be assigned inde-
tion E1, E2, E3 or E4 affixed to their Character of pendently for hull or machinery.
Classification.
1.6 Ships intended for navigation in polar waters
1.3 The requirements for the ice class notations may have the ice class notations PC7 – PC1 affixed to
E1 – E4 embody all necessary conditions to be complied their Character of Classification if the GL Guidelines
with for assignment of the ice classes IC – IA Super for the Construction of Polar Class Ships (I-1-22) are
according to the Finnish-Swedish Ice Class Rules 2010 complied with.
(23.11.2010 TRAFI / 31298 / 03.04.01.00 / 2010). Ref-
erence is also made to the Guidelines for the Applica- 1.7 Ships which beyond the requirements for the
tion of the Finnish-Swedish Ice Class Rules (see ice class notations E, E1 to E4 or PC7 to PC1 have
20.12.2011 TRAFI / 21816 / 03.04.01.01 / 2011). The been specially designed, dimensioned and/or equipped
ice class notations mentioned under 1.1 are equivalent for icebreaking will have affixed the notation
to the Finnish-Swedish ice classes in the following ICEBREAKER in addition. Dimensioning of the
way: structure with regard to the foreseen area of operation
has to be harmonized with GL.
Ice class notation E1 corresponds to ice class IC
Ice class notation E2 corresponds to ice class IB 1.8 If the scantlings required by this Section are
less than those required for ships without ice-
Ice class notation E3 corresponds to ice class IA strengthening, the scantlings required by the other
Sections of these Rules are to be maintained.
Ice class notation E4 corresponds to ice class IA Super

Note 2. Ice class draught for ships with notations

E1 – E4
The Swedish Maritime Administration has provided ice
class notations IBV and ICV for vessels navigating 2.1 The upper ice waterline (UIWL) is to be the
Lake Vänern (“Regulations and General Advice of the envelope of the highest points of the waterlines at
Swedish Maritime Administration on Swedish Ice Class which the ship is intended to operate in ice. The lower
for Traffic on Lake Vänern”, SJÖFS 2003:16). The ice waterline (LIWL) is to be the envelope of the low-
requirements for ice class notations IBV and ICV are est points of the waterlines at which the ship is in-
Chapter 1 Section 15 A Strengthening for Navigation in Ice I - Part 1
Page 15–2 GL 2012

tended to operate in ice. Both the UIWL and LIWL stage of construction before September 1st, 2003, the
may be broken lines. propulsion machinery output is not to be less than:

2.2 The maximum and minimum ice class P = f1 ⋅ f 2 ⋅ f3 ( f 4 ⋅ D + P0 ) [kW]

draughts at the forward perpendicular, amidships and
Pmin = 740 kW
at the aft perpendicular are to be determined in accor-
dance with the upper/lower ice waterlines and are to f1 = 1,0 for a fixed pitch propeller
be stated in the drawings submitted for approval. The
ice class draughts, the minimum propulsion machinery = 0,9 for a controllable pitch propeller
output, P, according to 3., as well as the corresponding ϕ1
ice class, will be stated in the Technical File to the f2 = + 0,675, but not more than 1,1
200
Class Certificate.
= 1,1 for a bulbous bow
If the summer load line in fresh water is anywhere
located at a higher level than the UIWL, the ship's f1 ⋅ f 2 ≥ 0,85
sides are to be provided with a warning triangle and
with an ice class draught mark at the maximum per- ϕ1 = the forward facing angle between the stem
missible ice class draught amidships (see Annex B). and the UIWL. If the stem forms a fair curve
within the ice belt as defined in 4.1, it may be
2.3 The draught and trim, limited by the UIWL, presented by a straight line between the
shall not be exceeded when the ship is navigating in ice. points of intersection of the stem with the up-
The salinity of the sea water along the intended route is per and lower limits of the ice belt. If there
to be taken into account when loading the ship. are sharp changes in the inclination of the
stem the largest ϕ1 is to be used.
The ship is always to be loaded down at least to the
LIWL when navigating in ice. The LIWL is to be B
agreed upon with the owners. Any ballast tank adja- f3 = 1, 2 , but not less than 1, 0
3
D
cent to the side shell and situated above the LIWL,
and needed to load the ship down to this waterline, is f4 and P0 are to be taken from Table 15.1 for the re-
to be equipped with devices to prevent the water from spective ice class notation and displacement.
freezing. In determining the LIWL, regard is to be
paid to the need for ensuring a reasonable degree of Table 15.1 Factor f4 and power P0 for the deter-
ice-going capability in ballast. The propeller is to be
mination of minimum propulsion ma-
fully submerged, entirely below the ice, if possible.
chinery output for ships of ice classes
E1 and E2
2.4 The minimum draught at the forward perpen-
dicular shall not be less than the smaller of the follow- Ice class
ing values: E2 E1 E2 E1
notation

Tmin = h 0 (2 + 2,5 ⋅ 10−4 ⋅ D) [m] D [t] < 30 000 ≥ 30 000

or f4 0,22 0,18 0,13 0,11
Tmin = 4 ⋅ h 0 [m] P0 370 0 3 070 2 100

D = displacement of the ship [t] based on a hori- D = displacement of the ship [t] as per 2.4. D need
zontal waterline passing through the maxi- not be taken greater than 80 000 t.
mum ice class draught amidships
For E2, no higher propulsion machinery output, P,
h0 = design ice thickness according to B.2.1 than required for E3 is necessary.

Note
3. Propulsion machinery output for ships The Finnish Administration may in special cases ap-
with notations E1 – E4 prove propulsion machinery output below that re-
quired in accordance with 3.2.
3.1 The propulsion machinery output, P, in the
context of this Section, is the total maximum output the 3.3 For ships with the ice class notation E1 or E2,
propulsion machinery can continuously deliver to the the keels of which are laid or which are in a similar
propeller(s). If the output of the machinery is restricted stage of construction on or after September 1st, 2003,
by technical means or by any regulations applicable to and for ships with the ice class notation E3 or E4, the
the ship, P is to be taken as the restricted output. propulsion machinery output is not to be less than:

3.2 For ships with the ice class notation E1 or E2,

the keels of which were laid or which were in a similar
I - Part 1 Section 15 A Strengthening for Navigation in Ice Chapter 1
GL 2012 Page 15–3

Pmin = 2 800 kW for ice class notation E4

( R CH /1000 )3/ 2
P = Ke [kW]
DP = 1 000 kW for ice class notations E1, E2
and E3
The required propulsion machinery output, P, is to be
For ice class notation E4:
calculated for ships on both the UIWL and the LIWL.
The propulsion machinery output shall not be less than B ⋅ L PAR
the greater of these two outputs. C1 = f1 + (1 + 0, 021 ϕ1 )
T
Ke = is to be taken from Table 15.2 2 + 1
B

Table 15.2 Factor Ke for the determination of ⋅ (f 2 ⋅ B + f 3 ⋅ L BOW + f 4 ⋅ B ⋅ L BOW )

minimum propulsion machinery out-
put for ships of ice classes E3 and E4 C2 = (1 + 0, 063 ϕ1 ) (g1 + g 2 ⋅ B)

Ke  T B2
+ g3 1 + 1, 2 
Propeller type CPP or electric  B Lpp
or FP
or hydraulic
machinery C3 = 845 kg/m2/s2
propulsion propeller
machinery C4 = 42 kg/m2/s2
1 propeller 2,03 2,26
C5 = 825 kg/s2
2 propellers 1,44 1,60
Cµ = 0,15 cos ϕ2 + sin ψ ⋅ sin α; Cµ ≥ 0,45
3 propellers 1,18 1,31
Cψ = 0,047 ψ – 2,115; Cψ = 0 for ψ ≤ 45°
The values in Table 15.2 apply only to conventional
propulsion systems. Other methods may be used for HF = thickness of the brash ice layer displaced by
determining the Ke values for advanced propulsion the bow [m]
systems as specified in 3.4.
DP = diameter of the propeller(s) [m] = 0, 26 + HM ⋅ B

RCH = resistance of the ship in a channel due to brash HM = thickness of the brash ice in mid channel [m]
ice and a consolidated layer [N]:
= 1,0 for ice class notations E3 and E4
2
R CH = C1 + C2 + C3 ⋅ Cµ (HF + HM ) = 0,8 for ice class notations E2

⋅ (B + Cψ ⋅ HF ) + C4 ⋅ LPAR ⋅ HF2 = 0,6 for ice class notation E1

3 The ship parameters defined below are to be calcu-

 Lpp ⋅ T  A wf lated on the UIWL using a horizontal waterline pass-
+ C5 
 B2  L
[N]
ing through the maximum ice class draught amidships,
  pp as defined in 2.1, and on the LIWL using a horizontal
waterline passing through the minimum ice class
C1 and C2 account for a consolidated upper layer of draught amidships, as defined in 2.3. The ship dimen-
the brash ice and can be taken as zero for ice class sions LPP and B, however, are always to be calculated
notations E1, E2 and E3. on the UIWL. See also Fig. 15.1.
Chapter 1 Section 15 A Strengthening for Navigation in Ice I - Part 1
Page 15–4 GL 2012

LBOW

Awf

B
a B/4

LPAR
buttock
at B/4
j1
j2

T
Fig. 15.1 Rake of the stem ϕ1 and rake of the bow ϕ2 at B/4 from CL

LPAR = length of the parallel midship body [m] the parameter DP/T, T shall be measured on the UIWL
amidships.
Lpp = length of the ship between perpendiculars [m]

new A.3.2
LBOW = length of the bow [m]
T = maximum and minimum ice class draughts Table 15.3 Range of application of the formula
amidship [m] according to 2.1 and 2.3, re- for ship resistance RCH
spectively
Parameter Minimum Maximum
A wf = area of the waterplane of the bow [m2]
α [°] 15 55
ϕ1 = the rake of the stem at the centreline [°]
ϕ1 [°] 25 90
For a ship with a bulbous bow, ϕ1 shall be
ϕ2 [°] 10 90
taken as 90°.
Lpp [m] 65,0 250,0
ϕ2 = the rake of the bow at B/4 [°], ϕ2max = 90°
B [m] 11,0 40,0
α = the angle of the waterline at B/4 [°]
T [m] 4,0 15,0
 tanϕ2  LBOW/Lpp 0,15 0,40
ψ = arctan  
 sinα  LPAR/Lpp 0,25 0,75
The quantity Dp/T 0,45 0,75
3 Awf/ (Lpp ⋅ B) 0,09 0,27
 Lpp ⋅ T 
 2

 B  3.4 For an individual ship, in lieu of the Ke or RCH
values defined in 3.3, the use of Ke values based on more
is not to be taken less than 5 and not to be taken more
exact calculations or RCH values based on model tests may
than 20.
be approved (see also paragraph 7.4 of the Guidelines
f1 = 23 [N/m2], g1 = 1 530 [N] for the Application of the Finnish-Swedish Ice Class
Rules). The model test report is to be submitted to GL.
f2 = 45,8 [N/m], g2 = 170 [N/m]
Such approvals will be given on the understanding
f3 = 14,7 [N/m], g3 = 400 [N/m1,5] that they can be revoked if warranted by the actual
f4 = 29 [N/m2] performance of the ship in ice.
The design requirement for ice classes is a minimum
Unless specially agreed with GL, ship's parameters are
speed of 5 knots in the following brash ice channels:
generally to be within the ranges of validity shown in
Table 15.3 if the above formula for RCH is to be used. E4: HM = 1,0 m and a 0,1 m thick consoli-
Otherwise, alternative methods for determining RCH dated layer of ice
are to be used as specified in 3.4. When calculating
I - Part 1 Section 15 A Strengthening for Navigation in Ice Chapter 1
GL 2012 Page 15–5

E3: HM = 1,0 m – c = 0,02 L,

not exceeding 2 m for the ice class notation E
E2: HM = 0,8 m
4.1.1.2 Midbody region
E1: HM = 0,6 m
The region from the aft boundary of the bow region,

new A.3.3 as defined in 4.1.1.1 to a line parallel to and at the
distance c aft of the borderline between the parallel
4. Definitions for ships with notations E1–E4 midbody region and the aft ship.
4.1 Ice belt 4.1.1.3 Stern region

4.1.1 The ice belt is the zone of the shell plating The region from the aft boundary of the midbody
which is to be strengthened. The ice belt is divided region, as defined in 4.1.1.2 to the stern.
into regions as follows, see Fig. 15.2: 4.1.1.4 Forefoot region
4.1.1.1 Bow region (for ice class notation E4 only)
The region from the stem to a line parallel to and at The region below the ice belt from the stem to a posi-
the distance c aft of the borderline between the parallel tion five main frame spaces abaft the point where the
midbody region and the fore ship: bow profile departs from the keel line.
– c = 0,04 L, 4.1.1.5 Upper bow ice belt region
not exceeding 6 m for the ice class notations E3
and E4, not exceeding 5 m for the ice class nota- (for ice class notations E3 and E4 and with a speed
tions E1 and E2 v0 ≥ 18 kn only)
0.2 L

2m
Ice belt,
midbody region
c Upper bow
ice belt

UIWL
Ice belt,
bow region
c LIWL
See 4.1.2
Fore foot

Border of the part of the side 5 frame spacings (s)

Ice belt, where waterlines are parallel
stern region to the centreline

Fig. 15.2 Ice belt

The region from the upper limit of the ice belt to 2 m

ℓ = unsupported span [m] of frames, web frames,
above it and from the stem to a position 0,2 L abaft
the forward perpendicular. stringer.

4.1.2 The vertical extension of the bow, midbody

and stern regions is to be determined from Table 15.4. p = design ice pressure [N/mm2] according to B.2.2

4.1.3 On the shell expansion plan submitted for ap-

proval, the location of the UIWL, LIWL and the upper/
h = design height of ice pressure area [m] accord-
lower limits of the ice belt, as well as the bow, midbody
ing to B.2.1
and stern regions (including forefoot and upper bow ice
belt regions, if applicable), are to be clearly indicated.

4.1.4 The following terms are used in the formulae The frame spacing and spans are normally to be meas-
in B.: ured in a vertical plane parallel to the centre-
line of the ship. However, if the ship's side
a = frame spacing [m], longitudinal or transverse, deviates more than 20° from this plane, the
taking into account the intermediate frames, frame spacing and spans shall be measured
if fitted. along the side of the ship.
Chapter 1 Section 15 B Strengthening for Navigation in Ice I - Part 1
Page 15–6 GL 2012

Table 15.4 Vertical extension of the bow, mid- 1.2 The formulae and values given in this Section
body and stern regions may be substituted by direct calculation methods if
they are deemed by GL to be invalid or inapplicable
Above Below for a given structural arrangement or detail. Other-
Ice class Hull wise, direct analysis is not to be utilised as an alterna-
UIWL LIWL
notation region tive to the analytical procedures prescribed by the
[m] [m]
explicit requirements in 3. (shell plating) and 4.
Bow (frames, ice stringers, web frames).
1,20
E4 Midbody 0,60
Direct analyses are to be carried out using the load
Stern 1,00 patch defined in 2. (p, h and ℓa). The pressure to be
Bow 0,90 used is 1.8 p, where p is determined according to 2.2.
E3 Midbody 0,50 The load patch is to be applied at locations where the
0,75 capacity of the structure under the combined effects of
Stern
bending and shear are minimized. In particular, the
Bow 0,70 structure is to be checked with the load centred on the
E2, E1, E Midbody 0,40 UIWL, 0.5 h0 below the LIWL, and several vertical
0,60
Stern locations in between. Several horizontal locations
shall also be checked, especially the locations centred
at the mid-span or mid-spacing. Further, if the load
length ℓa cannot be determined directly from the ar-
B. Requirements for the Notations E1 - E4 rangement of the structure, several values of ℓa shall
be checked using corresponding values for ca.
The acceptance criterion for designs is that the com-
1. General
bined stresses from bending and shear, using the von
Mises yield criterion, are lower than the yield strength
1.1 For transversely-framed plating, a typical ice ReH. When the direct calculation is performed using
load distribution is shown in Fig. 15.3. Due to differ- beam theory, the allowable shear stress is not to be
ences in the flexural stiffness of frames and shell plat- greater than 0.9 ⋅ τy, where τy = ReH / 3 .
ing, maximum pressures (pmax) occur at the frames
and minimum pressures occur between frames. 2. Ice loads

2.1 An ice-strengthened ship is assumed to oper-

pmax

ate in open sea conditions corresponding to a level ice

p

thickness not exceeding h0. The design ice load height,

h, of the area actually under ice pressure is, however,
pmin

assumed to be less than h0. The values for h0 and h are

0,75 · p = p1
given in Table 15.5.

Fig. 15.3 Ice load distribution Table 15.5 Ice thickness h0 and design ice load
height h
Due to the finite height of the design ice load, h (see
Table 15.5), the ice load distribution shown in Fig. 15.3 Ice class
is not applicable for longitudinally-framed plating. h0 [m] h [m]
notation

The formulae for determining the scantlings used in E, E1 0,4 0,22

this Section are based on the following design loads:
E2 0,6 0,25
for frames and longitudinally-framed shell plating: E3 0,8 0,30
E4 1,0 0,35
1
p = (pmax + p min ) [N / mm 2 ]
2
2.2 The design ice pressure is to be determined
according to the following formula:
for transversely-framed shell plating:
p = cd ⋅ c1 ⋅ ca ⋅ p0 [N / mm 2 ]
p1 = 0, 75 ⋅ p [N / mm 2 ]
a ⋅ k + b
cd = max. 1,0
p = design ice pressure as per 2.2 1 000
I - Part 1 Section 15 B Strengthening for Navigation in Ice Chapter 1
GL 2012 Page 15–7

D⋅P 3. Thickness of shell plating in the ice belt

k =
1 000 3.1 The thickness of the shell plating is to be
determined according to the following formulae:
Pmax = 740 kW for the ice class notation E
– transverse framing:
a, b = coefficients in accordance with Table 15.6
f1 ⋅ p1
t = 667 a + tc [mm]
Table 15.6 Coefficients a and b R eH

– longitudinal framing:
Region Bow Midbody and Stern
k p
≤ 12 > 12 ≤ 12 > 12 t = 667 a + tc [mm]
f 2 ⋅ R eH
a 30 6 8 2
b 230 518 214 286 p, p1 = see 1.1 and 2.2
4, 2
D = see A.2.4 f1 = 1,3 −
2
(1,8 + h a)
P = total maximum output the propulsion ma-
chinery can continuously deliver to the pro- f1max = 1,0
peller(s)[kW], see also A.3.1
0, 4
c1 = coefficient in accordance with Table 15.7 f 2 = 0,6 + , where h a ≤ 1
ha

0, 6 0, 4 h
ca = max. 1,0, min. 0,35 = 1, 4 − , where 1 < h a ≤ 1,8
ℓa a
tc = allowance for abrasion and corrosion [mm].
ℓa = effective length [m] according to Table 15.8 Usually tc amounts to 2 mm. If a special
coating is applied and maintained, which
p0 = 5,6 [N/mm2] (nominal ice pressure)
by experience is shown to be capable of
withstanding the abrasion of ice, the al-
Table 15.7 Coefficient c1 lowance may be reduced to 1 mm.

3.2 Where the draught is smaller than 1,5 m, e.g. in

Ice class Region the ballast condition, or where the distance between the
notation Bow Midbody Stern lower edge of the ice belt and the keel plate is smaller
than 1,5 m, the thickness of the bottom plating in way
E 0,3 –– –– of the bow region ice belt is not to be less than re-
quired for the ice belt. In the same area, the thickness
E1 1,0 0,50 0,25
of the plate floors is to be increased by 10 percent.
E2 1,0 0,70 0,45
3.3 Side scuttles are not to be situated in the ice
E3 1,0 0,85 0,65 belt. If the weather deck in any part of the ship is situ-
E4 1,0 1,0 0,75 ated below the upper limit of the ice belt, see A.4.1.2
(e.g. in way of the well of a raised quarter decker), the
bulwark is to have at least the same strength as is re-
quired for the shell in the ice belt. Special consideration
Table 15.8 Effective length ℓa has to be given to the design of the freeing ports.

Type of 3.4 For ships with the ice class notation E4, the
Structure ℓa forefoot region according to A.4.1.1.4 shall have at
framing
least the thickness of the midbody region.
transverse frame spacing
Shell 3.5 For ships with the ice class notation E3 or
longitudinal 1,7 × frame spacing E4, and with a speed v0 ≥ 18 kn, the upper bow ice
transverse frame spacing belt region according to A.4.1.1.5 shall have at least
Frames the thickness of the midbody region.
longitudinal span of frame
A similar strengthening of the bow region is also ad-
Ice stringer span of stringer visable for a ship with a lower service speed when it is
evident that the ship will have a high bow wave, e.g.
Web frame 2 × web frame spacing on the basis of model tests.
Chapter 1 Section 15 B Strengthening for Navigation in Ice I - Part 1
Page 15–8 GL 2012

4. Frames, ice stringers, web frames 4.1.3 For transverse framing above UIWL and
below LIWL, as well as longitudinal framing below
4.1 General LIWL, the vertical extension of the ice-strengthened
framing bE is to be determined according to Table 15.9.
4.1.1 Within the ice-strengthened area, all frames
are to be effectively attached to the supporting struc- Where the vertical extension of ice-strengthened trans-
tures. Longitudinal frames are generally to be attached verse framing bE would extend beyond a deck or a tank
to supporting web frames and bulkheads by brackets. top (or tank bottom) by not more than 250 mm, it may
Brackets may be omitted with an appropriate increase be terminated at that deck or tank top (or tank bottom).
in the section modulus of the frame (see 4.3.1) and
with the addition of heel stiffeners (heel stiffeners may Table 15.9 Vertical extension bE of ice-strength-
be omitted on the basis of direct calculations, subject
ened framing
to approval by GL). Brackets and heel stiffeners are to
have at least the same thickness as the web plate of the
frame and the free edge has to be appropriately stiff- bE
ened against buckling. When a transverse frame ter- Ice class Above Below
minates at a stringer or deck, a bracket or similar con- Hull region
notation UIWL LIWL
struction is to be fitted. When a frame is running
through the supporting structure, both sides of the web [m] [m]
are to be connected to the structure by direct welding, Down to double
collar plate or lug. Bow bottom or below
top of floors
4.1.2 For the ice class notation E4, for the ice class 1,2
notation E3 within the bow and midbody regions, and Midbody 2,0
for the ice class notations E2 and E1 within the bow E4
region, the following applies: Stern 1,6

4.1.2.1 Frames which are unsymmetrical, or having Upper bow Up to

webs which are not perpendicular to the shell plating, top of
ice belt1 ice belt
or having an unsupported span ℓ greater than 4,0 m,
are to be supported against tripping by brackets, inter- Bow 1,6
costal plates, stringers or similar at a distance not
exceeding 1300 mm. Midbody 1,0 1,3
E3, E2, Stern 1,0
4.1.2.2 The frames are to be attached to the shell by E1
double continuous welds. No scalloping is allowed
Upper bow Up to
except when crossing shell plate butt welds. top of
1
ice belt ice belt
4.1.2.3 The web thickness of the frames is not to be
less than the greater of the following values: E 1,0 1,0
1
tw1 = h w R eH / C [mm] If required according to A.4.1.1.5

where hw = web height [mm]

4.2 Transverse frames
C = 805 for profiles
4.2.1 The section modulus of a main, 'tweendeck or
C = 282 for flat bars
intermediate transverse frame is to be determined
tw2 = 25·a for transverse frames [mm] according to the following formula:
tw3 = half the thickness of the shell plating t [mm] p ⋅ a ⋅ h ⋅ ℓ
W = ⋅ 106 [cm3 ]
tw4 = 9 mm m t ⋅ R eH
For the purpose of calculating the web thickness of 7 ⋅ m0
frames, the yield strength ReH of the plating is not be mt =
h
taken greater than that of the framing. The minimum 7−5
web thickness of 9 mm is independent of the yield ℓ
strength ReH. m0 = coefficient according to Table 15.10
4.1.2.4 Where there is a deck, tank top (or tank bot- The boundary conditions referred to in Table 15.10 are
tom), bulkhead, web frame or stringer in lieu of a frame, those for the intermediate frames. Other boundary
its plate thickness is to be in accordance with .3 above, to conditions for main frames and 'tweendeck frames are
a depth corresponding to the height of adjacent frames. assumed to be covered by interaction between the
In the calculation of tw1, hw is to be taken as the height frames. This influence is included in the m0 values.
of adjacent frames and C is to be taken as 805. The load centre of the ice load is taken at ℓ/2.
I - Part 1 Section 15 B Strengthening for Navigation in Ice Chapter 1
GL 2012 Page 15–9

Table 15.10 Boundary conditions for transverse 4.2.3 Lower end of transverse framing
frames
4.2.3.1 The lower end of the ice-strengthened part of
all frames is to be attached to a deck, inner bottom,
Boundary tanktop (or tank bottom) or ice stringer as per 4.4.
condition m0 Example
4.2.3.2 Where an intermediate frame terminates
below a deck, tanktop (or tank bottom) or ice stringer
Frames in a bulk carrier which is situated at or below the lower limit of the ice
7 belt (see A.4.1.2), its lower end may be connected to
h

with top wing tanks

the adjacent main or 'tweendeck frames by a horizon-
tal member of the same scantlings as the main and
'tweendeck frames, respectively.

Frames extending from 4.3 Longitudinal frames

6 the tank top to a single
h

deck 4.3.1 The section modulus and the shear area of

longitudinal frames with all end conditions are to be
determined according to the following formulae:
section modulus:
Continuous frames be-
5,7 tween several decks or f 4 ⋅ p ⋅ h ⋅ ℓ2
h

stringers W= ⋅ 106 [cm3 ]

m ⋅ R eH
effective shear area:

Frames extending be- 3 ⋅ f 4 ⋅ f5 ⋅ p ⋅ h ⋅ ℓ

5 A= ⋅ 104 [cm 2 ]
h

tween two decks only

2 ⋅ R eH

The shear area of brackets is not to be taken into ac-

count when calculating the effective shear area of the
frames.
The effective shear area of a main, 'tweendeck or
intermediate transverse frame is to be determined f4 = factor which accounts for the distribution of
according to the following formula: load to adjacent frames
= 1 – 0,2 h/a
3 ⋅ f3 ⋅ p ⋅ h ⋅ a
A= ⋅ 104 [cm 2 ] f5 = factor which takes into account the maximum
2 ⋅ R eH shear force versus load location and the shear
stress distribution; to be taken as 2,16.
f3 = a factor which takes into account the maxi- m = boundary condition factor
mum shear force versus the load location and
= 13,3 for a continuous beam with double end
shear stress distribution; to be taken as 1,2.
brackets
Where less than 15 % of the frame span, ℓ, is situated = 11,0 for a continuous beam without double
within the ice-strengthened zone for frames as defined end brackets
in 4.1.3, ordinary frame scantlings may be used.
Where the boundary conditions are consid-
erably different from those of a continuous
4.2.2 Upper end of transverse framing beam, e.g. in an end field, a smaller factor m
may be determined
4.2.2.1 The upper end of the ice-strengthened part of
all frames is to be attached to a deck, tanktop (or tank 4.4 Ice stringers
bottom) or an ice stringer as per 4.4.
4.4.1 Ice stringers within the ice belt
4.2.2.2 Where a frame terminates above a deck or The section modulus and the shear area of a stringer
stringer, which is situated at or above the upper limit situated within the ice belt are to be determined ac-
of the ice belt (see A.4.1.2), the part above the deck or cording to the following formulae:
stringer need not be ice-strengthened. In such cases,
section modulus:
the upper part of the intermediate frames may be con-
nected to the adjacent main or 'tweendeck frames by a f6 ⋅ f7 ⋅ p ⋅ h ⋅ ℓ2
horizontal member of the same scantlings as the main W= ⋅ 106 [cm3 ]
and 'tweendeck frames, respectively. m ⋅ R eH
Chapter 1 Section 15 B Strengthening for Navigation in Ice I - Part 1
Page 15–10 GL 2012

effective shear area: p ⋅ h is not to be taken less than 0,15.

3 ⋅ f 6 ⋅ f 7 ⋅ f8 ⋅ p ⋅ h ⋅ ℓ f9 = factor which accounts for the distribution of

A= ⋅104 [cm 2 ]
2 ⋅ R eH load to the transverse frames; to be taken as
0,80
p ⋅ h is not to be taken less than 0,15.
m = see 4.3 f10 = safety factor of stringers; to be taken as 1,8
f6 = factor which accounts for the distribution of f11 = factor which takes into account the maximum
load to the transverse frames; to be taken as
shear force versus load location and the shear
0,9
stress distribution; to be taken as 1,2.
f7 = safety factor of stringers; to be taken as 1,8
m = see 4.3
f8 = factor which takes into account the maximum
shear force versus load location and the shear hs = distance of the stringer to the ice belt [m]
stress distribution; to be taken as 1,2.

4.4.2 Ice stringers outside the ice belt ℓs = distance of the stringer to the adjacent ice
stringer, deck or similar structure [m]
The section modulus and the shear area of a stringer
situated outside the ice belt, but supporting frames
subjected to ice pressure, are to be calculated accord- 4.4.3 Deck strips
ing to the following formulae:
4.4.3.1 Narrow deck strips abreast of hatches and
section modulus: serving as ice stringers are to comply with the section
modulus and shear area requirements in 4.4.1 and
f9 ⋅ f10 ⋅ p ⋅ h ⋅ ℓ 2  h s  6 4.4.2, respectively. In the case of very long hatches,
W= ⋅ 1 −  ⋅10 [cm3 ]
m ⋅ R eH  ℓs  the product p ⋅ h may be taken less than 0,15 but in no
case less than 0,10.
effective shear area:
4.4.3.2 When designing weatherdeck hatchcovers
3 ⋅ f9 ⋅ f10 ⋅ f11 ⋅ p ⋅ h ⋅ ℓ  h s  4 2 and their fittings, the deflection of the ship's sides due
A= ⋅ 1 −  ⋅10 [cm ]
2 ⋅ R eH  ℓs  to ice pressure in way of very long hatch openings
4.5 Web frames (greater than B/2) is to be considered.
3 ⋅ α ⋅ f13 ⋅ Q
4.5.1 The ice load transferred to a web frame from A= ⋅10 [cm 2 ]
R eH
a stringer or from longitudinal framing is to be calcu-
lated according to the following formula: Q = maximum calculated shear force under the ice
3 load P given in .1; to be taken as Q = P [kN]
P = f12 ⋅ p ⋅ h ⋅ e ⋅10 [kN]
α = see Table 15.11
p ⋅ h is not to be taken less than 0,15.
f13 = factor which takes into account the shear
e = web frame spacing [m] force distribution; to be taken as 1,1.
f12 = safety factor of web frame; to be taken as 1,8 section modulus:
In case the supported stringer is outside the ice belt,
M 1
the load P may be multiplied by W = ⋅ 103 [cm3 ]
R eH 2
 A 
 hs  1 − γ 
1 −   Aa 
 ℓs 
M = maximum calculated bending moment under
where hs and ℓs shall be taken as defined in 4.4.2. the ice load P given in .1; to be taken as M =
0,193·P·ℓ [kNm]
4.5.2 Shear area and section modulus Aa = actual shear area, Aa = Af + Aw
The shear area and section modulus of web frames are
to be calculated according to the following formulae: γ = see Table 15.11

effective shear area:

I - Part 1 Section 15 B Strengthening for Navigation in Ice Chapter 1
GL 2012 Page 15–11

5. Stem 5.2 The plate thickness of a shaped plate stem

and, in the case of a blunt bow, any part of the shell
5.1 The stem is to be made of rolled, cast or where α ≥ 30° and ψ ≥ 75° (see A.3.3 for definitions),
forged steel, or of shaped steel plates (see Fig. 15.4). is to be calculated according to the formulae in 3.1
observing that:
p1 = p
a = smaller of the two unsupported widths of the
plate panel [m]
ℓa = spacing of vertical supporting elements [m]
(see also Table 15.8)

5.3 The stem, and the part of a blunt bow defined

in 5.2 (if applicable), are to be supported by floors or
brackets spaced not more than 0,6 m apart and having
a thickness of at least half the plate thickness accord-
ing to 5.2. The reinforcement of the stem shall extend
from the keel to a point 0,75 m above UIWL or, in
Fig. 15.4 Stem case an upper bow ice belt is required (see also
A.4.1.1), to the upper limit of the upper bow ice belt
region.

Table 15.11 Coefficient α and γ for the calculation of required shear area and section modulus

Af
0,00 0,20 0,40 0,60 0,80 1,00 1,20 1,40 1,60 1,80 2,00
Aw
α 1,50 1,23 1,16 1,11 1,09 1,07 1,06 1,05 1,05 1,04 1,04

γ 0,00 0,44 0,62 0,71 0,76 0,80 0,83 0,85 0,87 0,88 0,89
Af = actual cross sectional area of free flange
Aw = actual effective cross sectional area of web plate
6. Stern
7. Rudder and steering gear
6.1 Propulsion arrangements with azimuthing
thrusters or "podded" propellers, which provide an
improved manoeuvrability, result in increased ice
loading of the stern region.
7.1 When calculating the rudder force and tor-
Due consideration is to be given to this increased ice sional moment according to Section 14, B.1. the ship's
loading in the design and dimensioning of the stern speed v0 is not to be taken less than that given in Ta-
region and aft structure. ble 15.12.

6.2 In order to avoid very high loads on propeller

blade tips, the minimum distance between propeller(s)
and hull (including stern frame) should not be less All scantlings dimensioned according to the rudder
than h0 (see 2.1). force and the torsional moment respectively (rudder
stock, rudder coupling, rudder horn etc.) as well as the
capacity of the steering gear are to be increased ac-
6.3 On twin and triple screw ships, the ice- cordingly where the speed stated in Table 15.12 ex-
strengthening of the shell and framing shall be ex- ceeds the ship's service speed.
tended to the double bottom to an extent of 1,5 m
forward and aft of the side propellers.

6.4 Shafting and stern tubes of side propellers are Independent of rudder profile the coefficient κ2 ac-
generally to be enclosed within plated bossings. If cording to Section 14, B.1.1 need not be taken greater
detached struts are used, their design, strength and than κ2 = 1,1 in connection with the speed values
attachment to the hull are to be duly considered. given in Table 15.12.
Chapter 1 Section 15 C Strengthening for Navigation in Ice I - Part 1
Page 15–12 GL 2012

Table 15.12 Minimum speed for the dimensioning Any portion of the grid located within the icebelt may
of rudder be subjected to loads arising from intact ice and is to
be specially considered.
v0
Ice class notation
[kn]
E1 14 8.2 For a grid of standard construction, inter-
costal bars are to be fitted perpendicular to continuous
E2 16 bars (see Fig. 15.5). Continuous and intercostal bars
E3 18 are to be evenly spaced not more than sc, max = si, max =
E4 20 500 mm (minimum 2 × 2 bars).

The factor κ3 according to Section 14, B.1.1 need not The grid is not to protrude outside the surface of the
be taken greater than 1,0 for rudders situated behind a hull and it is recommended to align continuous bars
nozzle. with the buttock lines at the leading edge of the
thruster tunnel (see Fig. 15.5).
7.2 The local scantlings of rudders are to be de-
termined assuming that the whole rudder belongs to
the ice belt (as per A.4.1). Further, the rudder plating Grids of non-standard construction are to have an
and frames are to be designed using the ice pressure p equivalent strength to that of the standard configura-
for the plating and framing in the midbody region (see tion described in .3.
2.2). The thickness of webs shall not be less than half
the rudder plating thickness. 8.3 The section modulus of continuous bars, Wc,
is not to be less than
7.3 For the ice class notations E3 and E4, the
rudder stock and the upper edge of the rudder are to be
protected from direct contact with intact ice by an ice sc ⋅ D2
Wc = ⋅ (1 − κ) ⋅ 10−4 , min . 35 [cm3 ]
knife that extends below the LIWL, if practicable (or 4 ⋅ R eH
equivalent means). Special consideration shall be
given to the design of the rudder and the ice knife for
vessels with a flap-type rudder. where

7.4 For ships with the ice class notations E3 and

E4, due regard is to be paid to the excessive loads sc = spacing of continuous bars [mm]
arising when the rudder is forced out of the midship
position while going astern in ice or into an ice ridge. D = diameter of thruster tunnel [mm]
Suitable arrangements such as rudder stoppers or
locking devices (see Section 14, G.2.) are to be in-
stalled to absorb these loads. Ii s c
κ = 0, 4 ⋅ ⋅ , max . 0,5
Ic si
Note
For ships sailing in low temperature areas, small gaps where
between the rudder and ship's hull may cause the rudder
to become fixed to the hull through freezing. It is there-
fore recommended to avoid gaps less than 1/20 of the Ii/Ic = ratio of moments of inertia of intercostal and
rudder body width or 50 mm, whichever is less, or to continuous bars
install suitable means such as heating arrangements.

sc/si = ratio of spacings of continuous and intercos-

8. Lateral thruster grids
tal bars

8.1 The following requirements apply in case ice-

strengthening of lateral thruster grids is required (see GL
Rules for Machinery Installations (I-1-2), Section 13, C.). C. Requirements for the Notation E
In general, lateral thruster tunnels are to be located
outside the icebelt defined in A.4.1 by the bow, mid-
body, and stern regions, as well as the forefoot region 1. Shell plating within the ice belt
for ice class notation E4. Grids installed at the inlets of
such tunnels may be subjected to loads arising from
broken ice and are to be designed according to .2 and 1.1 Within the ice belt the shell plating shall have
.3 below. a strengthened strake extending over the bow region
I - Part 1 Section 15 C Strengthening for Navigation in Ice Chapter 1
GL 2012 Page 15–13

the thickness of which is to be determined according 2.2 Tripping brackets spaced not more than 1,3 m
to B.3. apart are to be fitted within the ice belt in line with the
tiers of beams and stringers required in Section 9, A.5.
in order to prevent tripping of the frames. The tripping
1.2 The midship thickness of the side shell plat- brackets are to be extended over the bow region.
ing is to be maintained forward of amidships up to the
strengthened plating.
3. Stem

2. Frames The thickness of welded plate stems up to 600 mm

above UIWL is to be 1,1 times the thickness required
according to Section 13, B.2., however, need not ex-
2.1 In the bow region the section modulus of the ceed 25 mm. The thickness above a point 600 mm
frames is to comply with the requirements given in above the UIWL may be gradually reduced to the
B.4. Continuous Bars according to Section 13, B.2.
thickness required

Intercostal Bars

Buttock Lines

si
sc

Fig. 15.5 Standard construction of lateral thruster grid

I - Part 1 Section 16 A Superstructures and Deckhouses Chapter 1
GL 2012 Page 16–1

Section 16

Superstructures and Deckhouses

A. General
1.9 Throughout this Section the following defini-
1. Definitions tions apply:

k = material factor according to Section 2, B.2.

1.1 A superstructure is a decked structure on the
freeboard deck extending from side to side of the ship ps = load according to Section 4, B.2.1
or with the side plating not being inboard of the shell
plating more than 0,04 B.
pe = load according to Section 4, B.2.2

new A.2
pD = load according to Section 4, B.1.
1.2 A deckhouse is a decked structure above the
strength deck the side plating being inboard of the pDA = load according to Section 4, B.5.
shell plating more than 0,04 B.
pL = load according to Section 4, C.1.

new A.2
tK = corrosion addition according to Section 3, K.
1.3 A long deckhouse is a deckhouse the length
of which within 0,4 L amidships exceeds 0,2 L or
new A.2
12 m, where the greater value is decisive. The strength
of a long deckhouse is to be specially considered. 2. Arrangement of superstructure

new A.2
2.1 According to ICLL, Regulation 39, a mini-
1.4 A short deckhouse is a deckhouse not cov- mum bow height is required at the forward perpendicu-
ered by the definition given in 1.3. lar, which may be obtained by sheer extending for at
least 0,15 Lc, measured from the forward perpendicu-

new A.2 lar, or by fitting a forecastle extending from the stem to
a point at least 0,07 Lc abaft the forward perpendicular.
1.5 Superstructures extending into the range of
0,4 L amidships and the length of which exceeds
new Section 27, C.5.1
0,15 L are defined as effective superstructures.

new A.2 2.2 Ships carrying timber deck cargo and which
are to be assigned the respective permissible freeboard,
Their side plating is to be treated as shell plating and are to have a forecastle of the Rule height and a length
their deck as strength deck (see Sections 6 and 7). of at least 0,07 Lc. Furthermore, ships the length of

new D.1 which is less than 100 m, are to have a poop of Rule
height or a raised quarter deck with a deckhouse.
1.6 All superstructures being located beyond
0,4 L amidships or having a length of less than 0,15 L
new Section 27, C.5.2
or less than 12 metres are, for the purpose of this Sec-
tion, considered as non-effective superstructures. 3. Strengthenings at the ends of superstructures

new A.2
3.1 At the ends of superstructures one or both end
1.7 For deckhouses of aluminium, Section 2, D.
is to be observed. For the use of non-magnetic mate- bulkheads of which are located within 0,4 L amid-
ships, the thickness of the sheer strake, the strength
rial in way of the wheel house see Section 14, A.1.4.
deck in a breadth of 0,1 B from the shell, as well as

new A.1 Note the thickness of the superstructure side plating are to
be strengthened as specified in Table 16.1. The
1.8 Scantlings of insulated funnels are to be de- strengthenings shall extend over a region from 4 frame
termined as for deckhouses. spacings abaft the end bulkhead to 4 frame spacings
forward of the end bulkhead.

new H

new B.1
Chapter 1 Section 16 B Superstructures and Deckhouses I - Part 1
Page 16–2 GL 2012

Table 16.1 Strengthening [%] at the ends of super- 6.2 The natural frequencies of local deck panel
structures structure components (plates, stiffeners, deck frames,
longitudinal girders, deck grillages) should not coincide
Type of strength deck side plating of with major excitation frequencies at the nominal revolu-
superstructure and sheer strake superstructure tion rate of the propulsion plant. This should be verified
effective 30 20 during the design stage by a local vibration analysis 1.
according 1.5
new J.2
non-effective 20 10
according 1.6 6.3 It is recommended to design the local deck
structures in such a way that their natural frequencies
exceed twice propeller blade rate, and in case of rigidly
3.2 Under strength decks in way of 0,6 L amid- mounted engines ignition frequency, by at least 20 %.
ships, girders are to be fitted in alignment with longi- This recommendation is based on the assumption of a
tudinal walls, which are to extend at least over three propeller with normal cavitation behaviour, i.e. sig-
frame spacings beyond the end points of the longitu- nificant decrease of pressure pulses with increasing
dinal walls. The girders are to overlap with the longi- blade harmonic shall be ensured.
tudinal walls by at least two frame spacings.

new J.3

new B.2
6.4 Cantilever navigation bridge wings should be
4. Transverse structure of superstructures supported by pillars or brackets extending from the outer
and deckhouses wing edge to at least the deck level below. If this is not
possible, the attachment points of the pillars/ brackets at
The transverse structure of superstructures and deck- the deckhouse structure have to be properly supported.
houses is to be sufficiently dimensioned by a suitable
arrangement of end bulkheads, web frames, steel walls
new J.4
of cabins and casings, or by other measures.
6.5 The base points of the main mast located on

new C the compass deck should be preferably supported by
walls or pillars. The natural frequencies of the basic
5. Openings in closed superstructures main mast vibration modes (longitudinal, transverse,
torsional) should not coincide with major excitation
5.1 All access openings in end bulkheads of closed frequencies at the nominal revolution rate of the pro-
superstructures shall be fitted with weather tight doors pulsion plant. This should be verified during the de-
permanently attached to the bulkhead, having the same sign stage by a mast vibration analysis.
strength as the bulkhead. The doors shall be so arranged

new J.5
that they can be operated from both sides of the bulk-
head. The coaming heights of the access opening above
the deck are to be determined according to ICLL.
B. Side Plating and Decks of Non-Effective

new Section 21, R.1
Superstructures
5.2 Any opening in a superstructure deck or in a
1. Side plating
deckhouse deck directly above the freeboard deck
(deckhouse surrounding companionways), is to be 1.1 The thickness of the side plating above the
protected by efficient weather tight closures. strength deck is not to be less than the greater of the

new Section 21, R.2 following values:

t = 1, 21 ⋅ a p ⋅ k + tK [mm]
5.3 Weathertight doors in Load Line Position 1
and 2 according to ICLL shall be generally equivalent or
to the international standard ISO 6042. t = 0,8 ⋅ t min [mm]

new Section 21, R.1
p = ps or pe, as the case may be
6. Recommendations regarding deckhouse tmin = see Section 6, B.3.1
vibration

new D.2.1.1
6.1 The natural frequencies of the basic global
deckhouse vibration modes (longitudinal, transverse,
torsional) should not coincide with major excitation
frequencies at the nominal revolution rate of the pro-
pulsion plant. This should be verified during the de- 1 The natural frequencies of plate fields and stiffeners can be
sign stage by a global vibration analysis. estimated by POSEIDON or by means of the software tool
GL LocVibs which can be downloaded from the GL homepage

new J.1 www.gl-group.com/gl-locvibs.
I - Part 1 Section 16 C Superstructures and Deckhouses Chapter 1
GL 2012 Page 16–3

1.2 The thickness of the side plating of upper tier protection for openings as per Regulation 18 of ICLL
superstructures may be reduced if the stress level and for accommodations. These requirements also ap-
permits such reduction. ply to breakwaters, see also F.

new D.2.1.2
new E.1

2. Deck plating
2. Definitions
2.1 The thickness of deck plating is not to be less
than the greater of the following values: The design load for determining the scantlings is:

t = C ⋅ a p ⋅ k + tK [mm]
pA = n ⋅ c ( b ⋅ cL ⋅ co − z ) [kN / m 2 ]
= ( 5,5 + 0, 02 L ) ⋅ k [mm]
cL and co see Section 4, A.2.2
p = pDA or pL, the greater value is to be taken.
hN = standard superstructure height
C = 1, 21, if p = p DA
= 1, 05 + 0, 01 L [m], 1,8 ≤ h N ≤ 2,3
= 1,10, if p = pL
L need not be taken greater than 200 m. L
n = 20 +
12

new D.2.2.1
for the lowest tier of unprotected fronts. The
2.2 Where additional superstructures are ar- lowest tier is normally that tier which is di-
ranged on non-effective superstructures located on the rectly situated above the uppermost continu-
strength deck, the thickness required by 2.1 may be ous deck to which the Rule depth H is to be
reduced by 10 per cent. measured. However, where the actual dis-
tance H – T exceeds the minimum non-

new D.2.2.2
corrected tabular freeboard according to
ICLL by at least one standard superstructure
2.3 Where plated decks are protected by sheath- height hN, this tier may be defined as the 2nd
ing, the thickness of the deck plating according to 2.1
tier and the tier above as the 3rd tier.
and 2.2 may be reduced by tK, however, it is not to be
less than 5 mm. L
= 10 +
Where a sheathing other than wood is used, attention 12
is to be paid that the sheathing does not affect the
steel. The sheathing is to be effectively fitted to the for 2nd tier unprotected fronts
deck.
L

new D.2.2.3 = 5+
15

3. Deck beams, supporting deck structure, for 3rd tier and tiers above of unprotected
frames fronts, for sides and protected fronts
3.1 The scantlings of the deck beams and the L x
supporting deck structure are to be determined in = 7 + − 8
accordance with Section 10. 100 L

new D.2.3.1 for aft ends abaft amidships

3.2 The scantlings of superstructure frames are L x

given in Section 9, A.3. = 5 + − 4
100 L

new D.2.3.2
for aft ends forward of amidships

L
C. Superstructure End Bulkheads and Deck- = 10 +
20
house Walls
x
1. General for breakwaters forward of ≥ 0,85
L
The following requirements apply to superstructure
end bulkheads and deckhouse walls forming the only L need not be taken greater than 300 m.
Chapter 1 Section 16 C Superstructures and Deckhouses I - Part 1
Page 16–4 GL 2012

2 Table 16.2 Minimum design load pAmin

x 
 L − 0, 45  x
b = 1, 0 +   for < 0, 45 pAmin [kN/m2] for
 CB + 0, 2  L
 
2 unprotected
x  L other areas
 L − 0, 45  x fronts
= 1, 0 + 1,5   for ≥ 0, 45
 CB + 0, 2  L
  lowest higher tier tier
4th tier
tier tiers ≤ 3rd ≥ 5th
2
x 
 L − 0, 45  ≤ 50 30 15
= 1, 0 + 2, 75  
 CB + 0, 2 
  > 50
L L
25 + 12,5 12,5 + 12,5 8,5
x 10 20
for breakwaters forward of ≥ 0,85 ≤ 250 but not
L less than
in other
0,60 ≤ CB ≤ 0,80; when determining scantlings of > 250 50 25
areas
aft ends forward of amidships,
CB need not be taken less than
0,8.
3. Scantlings
x = distance [m] between the bulkhead consid-
ered or the breakwater and the aft end of the 3.1 Stiffeners
length L. When determining sides of a deck-
house, the deckhouse is to be subdivided into The section modulus of the stiffeners is to be deter-
parts of approximately equal length, not ex- mined according to the following formula:
ceeding 0,15 L each, and x is to be taken as
the distance between aft end of the length L W = 0,35 ⋅ a ⋅ ℓ 2 ⋅ pA ⋅ k [cm3 ]
and the centre of each part considered. These requirements assume the webs of lowest tier
z = vertical distance [m] from the summer load stiffeners to be effectively welded to the decks. Scant-
line to the midpoint of stiffener span, or to lings for other types of end connections may be spe-
the middle of the plate field cially considered.
b' The section modulus of house side stiffeners needs not
c = 0,3 + 0, 7 to be greater than that of side frames on the deck situ-
B'
ated directly below; taking account of spacing a and
For exposed parts of machinery casings and breakwa- unsupported span ℓ.
ters, c is not to be taken less than 1,0.

new E.2.2
b' = breadth of deckhouse at the position consid-
ered 3.2 Plate thickness
B' = actual maximum breadth of ship on the ex- The thickness of the plating is to be determined ac-
posed weather deck at the position consid- cording to the following formula:
ered.
b'/B' is not to be taken less than 0,25. t = 0,9 ⋅ a p A ⋅ k + t K [mm]
a = spacing of stiffeners [m]
ℓ = unsupported span [m]; for superstructure end  L 
t min =  5, 0 +  k [mm]
bulkheads and deckhouse walls, ℓ is to be  100 
taken as the superstructure height or deck-
house height respectively, however, not less for the lowest tier and for breakwaters
than 2,0 m.
 L 
The design load pA is not to be taken less than the t min =  4, 0 +  k [mm]
minimum values given in Table 16.2. For breakwaters,  100 
the minimum design load is to be the same as that for
for the upper tiers, however, not less than
the lowest tier of unprotected fronts. 5,0 mm.

new Section 4, B.8 and B.9
I - Part 1 Section 16 E Superstructures and Deckhouses Chapter 1
GL 2012 Page 16–5

L need not be taken greater than 300 m. 1.5 Electric cables are to be fitted in bends in
order to facilitate the movement. The minimum bend-

new E.2.1
ing radius prescribed for the respective cable is to be
observed. Cable glands are to be watertight. For fur-
ther details, see the GL Rules for Electrical Installa-
tions (I-1-3).
D. Decks of Short Deckhouses

new G.1.5
1. Plating
1.6 The following scantling requirements for
The thickness of deck plating exposed to weather but rails, mountings, securing devices, stoppers and sub-
not protected by sheathing is not to be less than: structures in the hull and the deckhouse bottom apply
to ships in unrestricted service. For special ships and
t = 8 ⋅ a k + tK [mm] for ships intended to operate in restricted service
For weather decks protected by sheathing and for ranges requirements differing from those given below
decks within deckhouses the thickness may be reduced may be applied.
by tK.
new G.1.6
In no case the thickness is to be less than the minimum
thickness tmin = 5,0 mm. 2. Design loads

new F.1 For scantling purposes the following design loads
apply:
2. Deck beams
2.1 Weight
The deck beams and the supporting deck structure are
to be determined according to Section 10. 2.1.1 The weight induced loads result from the
weight of the fully equipped deckhouse, considering

new F.2
also the acceleration due to gravity and the accelera-
tion due to the ship's movement in the seaway. The
weight induced loads are to be assumed to act in the
E. Elastic Mounting of Deckhouses centre of gravity of the deckhouse.
The individual dimensionless accelerations az (verti-
1. General cally), ay (transversely) and ax (longitudinally) and the
dimensionless resultant acceleration aß, are to be de-
1.1 The elastic mountings are to be type ap- termined according to Section 4, E. for k = 1,0 and
proved by GL. The stresses acting in the mountings f = 1,0.
which have been determined by calculation are to be
proved by means of prototype testing on testing ma- Due to the resultant acceleration aß the following load
chines. Determination of the grade of insulation for is acting:
transmission of vibrations between hull and deck- P = G ⋅ a ß ⋅ g [kN]
houses is not part of this type approval.

new G.1.1 G = mass of the fully equipped deckhouse [t]
g = 9,81 [m/s2]
1.2 The height of the mounting system is to be
such that the space between deck and deckhouse bot-
new G.2.1.1
tom remains accessible for repair, maintenance and
inspection purposes. The height of this space shall 2.1.2 The support forces in the vertical and hori-
normally not be less than 600 mm. zontal directions are to be determined for the various
angles ß. The scantlings are to be determined for the

new G.1.2 respective maximum values (see also Fig. 16.1).

new G.2.3.2
1.3 For the fixed part of the deckhouse on the
weather deck, a coaming height of 380 mm is to be
observed, as required by ICLL for coamings of doors
in superstructures which do not have access openings
to under deck spaces.

new G.1.3

1.4 For pipelines, see the GL Rules for Machin-

ery Installations (I-1-2), Section 11.

new G.1.4
Chapter 1 Section 16 E Superstructures and Deckhouses I - Part 1
Page 16–6 GL 2012

Az, Bz, Ay, By – below the deckhouse: load pu according to the

pressure head due to the distance between the
Bz supporting deck and the deckhouse bottom
[kN/m2]
By – outside the deckhouse: load pD

Ay – bearing forces in accordance with the load as-

sumptions 2.1 and 2.2
Az
b
new G.2.5

Fig. 16.1 Support forces

3. Load cases

2.2 Water pressure and wind pressure 3.1 For design purposes the following load cases
are to be investigated separately (see also Fig. 16.2):
2.2.1 The water load due to the wash of the sea is
assumed to be acting on the front wall in the longitu-
new G.2.3.1 and G.3
dinal direction only. The design load is:
C. L.
p wa = 0,5 ⋅ pA [kN / m 2 ]
Py Px pwa
pA = see C.2. pwi
Pz Pz
The water pressure is not to be less than: Ay By 0,5 · pA
pwa = 25 [kN/m2] at the lower edge of the Ax (Bx)
Az Bz Az (Bz)
front wall
= 0 at the level of the first Fig. 16.2 Design loads due to wind and water
tier above the deck- pressure
house bottom

Pwa = pwa ⋅ Af [kN] 3.2 Service load cases

Forces due to external loads:

Af = loaded part of deckhouse front wall [m2]
3.2.1 Transverse direction (z-y-plane)

new G.2.2.1

2.2.2 The design wind load acting on the front wall Py1 = G ⋅ a ß( y ) ⋅ g + Pwi [kN]
and on the side walls is:
acting in transverse direction
Pwi = A D ⋅ p wi [kN]
Pz1 = G ⋅ a ß( z ) ⋅ g [kN]
AD = area of wall [m2]
acting vertically to the baseline
pwi = 1,0 [kN/m2]
Pwi = wind load as per 2.2.2

new G.2.2.2
aß(y) = horizontal acceleration component of aß
2.3 Load on the deckhouse bottom aß(z) = vertical acceleration component of aß
The load on the deckhouse bottom is governed by the

new G.3.1
load acting on the particular deck on which the deck-
house is located. Additionally, the support forces
resulting from the loads specified in 2.1 and 2.2 are to 3.2.2 Longitudinal direction (z-x-plane)
be taken into account.
Px1 = G ⋅ a ß( x ) ⋅ g + Pwa + Pwi [kN]

new G.2.4
acting in longitudinal direction
2.4 Load on deck beams and girders
For designing the deck beams and girders of the deck Pz1 = G ⋅ a ß( z ) ⋅ g [kN]
on which the deckhouse is located the following loads
are to be taken: acting vertically to the baseline
I - Part 1 Section 16 E Superstructures and Deckhouses Chapter 1
GL 2012 Page 16–7

aß(x) = horizontal acceleration component in the 4.1.2 Strength calculations for the structural ele-
longitudinal plane ments with information regarding acting forces are to
be submitted for approval.

new G.3.1

new G.4.1.2
3.2.3 For designing the securing devices to prevent
the deckhouse from being lifted, the force (in upward
direction) is not to be taken less than determined from 4.2 Permissible stresses
the following formula:
4.2.1 The permissible stresses given in Table 16.3
Pz min = 0,5 ⋅ g ⋅ G [kN] are not to be exceeded in the rails and the steel struc-
tures of mounting elements and in the substructures

new G.3.2 (deck beams, girders of the deckhouse and the deck,
on which the deckhouse is located).
3.3 Extraordinary load cases
new G.4.2.1
3.3.1 Collision force in longitudinal direction
Table 16.3 Permissible stress in the rails and the
Px2 = 0,5 ⋅ g ⋅ G [kN] steel structures at mounting elements
and in the substructures [N/mm2]

new G.3.3.1

3.3.2 Forces due to static heel of 45° extra-

service load
Type of stress ordinary
cases
Pz2 , Py2 = 0,71 ⋅ g ⋅ G [kN] load cases

0,6 ⋅ ReH 0,75 ⋅ ReH

Pz2 = force acting vertically to the baseline
normal stress σn or or
Py2 = force acting in transverse direction 0,4 ⋅ Rm 0,5 ⋅ Rm

new G.3.3.2 0,35 ⋅ ReH 0,43 ⋅ ReH
shear stress τ or or
3.3.3 The possible consequences of a fire for the 0,23 ⋅ Rm 0,3 ⋅ Rm
elastic mounting of the deckhouse are to be examined
(e.g. failure of rubber elastic mounting elements, melt- equivalent stress:
ing of glue). Even in this case, the mounting elements 0,75 ⋅ ReH 0,9 ⋅ ReH
σv = σn2 + 3 τ2
between hull and deckhouse bottom shall be capable
of withstanding the horizontal force Py2 as per 3.3.2 in
transverse direction.
4.2.2 The permissible stresses for designing the

new G.3.3.3 elastic mounting elements of various systems will be
considered from case to case. Sufficient data are to be
3.3.4 For designing of the securing devices to pre- submitted for approval.
vent the deckhouse from being lifted, a force not less
than the buoyancy force of the deckhouse resulting
new G.4.2.2
from a water level of 2 m above the freeboard deck is
to be taken.
4.2.3 The stresses in the securing devices to pre-

new G.3.3.4 vent the deckhouse from being lifted are not to exceed
the stress values specified in 4.2.1.
4. Scantlings of rails, mounting elements and
substructures
new G.4.2.3

4.1 General 4.2.4 In screwed connections, the permissible

stresses given in Table 16.4 are not to be exceeded.
4.1.1 The scantlings of those elements are to be
determined in accordance with the load cases stipu-
new G.4.2.4
lated under 3. The effect of deflection of main girders
need not be considered under the condition that the 4.2.5 Where turnbuckles in accordance with DIN
deflection is so negligible that all elements take over 82008 are used for securing devices, the load per bolt
the loads equally. under load conditions 3.2.3 and 3.3.4 may be equal to

new G.4.1.1 the proof load (2 times safe working load).

new G.4.2.5
Chapter 1 Section 16 F Superstructures and Deckhouses I - Part 1
Page 16–8 GL 2012

Table 16.4 Permissible stress in screwed connec- aw

tions [N/mm2] hw

extra-
service load
Type of stress ordinary z
cases
load cases
longitudinal tension σn 0,5 ⋅ ReH 0,8 ⋅ ReH T
bearing pressure pℓ 1,0 ⋅ ReH 1,0 ⋅ ReH Fig. 16.3 Whaleback
equivalent stress from However, IMO requirements regarding navigation
longitudinal tension σn, bridge visibility are to be considered.
tension τt due to tighten-
new I.2.1
ing torque and shear τ, 0,6 ⋅ ReH 1,0 ⋅ ReH
if applicable: 2.2 The breakwater has to be at least as broad as
the width of the area behind the breakwater, intended
σv = σn2 + 3 τ2 + τt2
( ) for carrying deck cargo.

new I.2.2
5. Corrosion addition
3. Cutouts
For the deck plating below elastically mounted deck-
houses a minimum corrosion addition of tK = 3,0 mm Cutouts in the webs of primary supporting members of
applies. the breakwater are to be reduced to their necessary
minimum. Free edges of the cutouts are to be rein-

new G.5 forced by stiffeners.
If cutouts in the plating are provided to reduce the load
F. Breakwater on the breakwater, the area of single cutouts should
not exceed 0,2 m2 and the sum of the cutout areas not
1. Arrangement 3 % of the overall area of the breakwater plating.

If cargo is intended to be carried on deck forward of
new I.4

x
≥ 0,85, a breakwater or an equivalent protecting struc- 4. Loads
L
ture (e.g. whaleback or turtle deck) is to be installed.
4.1 The loads for dimensioning are to be taken

new I.1 from C.2.

2. Dimensions of the breakwater 4.2 For breakwaters with an inclining angle αw

of less than 90° and for whalebacks with αw > 20°
2.1 The recommended height of the breakwater is pA ⋅ sin αw is to be applied with pA according to C.2.
αw is to be determined on centre line.
hW = 0,8 (b ⋅ c L ⋅ c0 − z) [m].

new Section 4, B.9.1
The minimum breakwater height shall not be less than
4.3 For whalebacks with an inclining angle αw of
h W min = 0, 6 (b ⋅ cL ⋅ c0 − z) [m], less than 20° the loads according to Section 4, B.5. are
to be applied as for forecastle decks.
but need not to be more than the maximum height of
the deck cargo stowed between the breakwater and 15
new Section 4, B.9.2
m aft of it.
z is to be the vertical distance [m] between the summer 5. Plate thickness and stiffeners
load line and the bottom line of the breakwater.
5.1 The plate thickness has to be determined
cL and c0 see Section 4, A.2.2. according to C.3.2.
The average height of whalebacks or turtle decks has
new I.3.1.1
to be determined analogously according to Fig. 16.3.
5.2 The section moduli of stiffeners are to be
calculated according to C.3.1. Stiffeners are to be
connected on both ends to the structural members
supporting them.

new I.3.2.1 and I.3.2.2
I - Part 1 Section 16 F Superstructures and Deckhouses Chapter 1
GL 2012 Page 16–9

6.2 Sufficient supporting structures are to be pro-

5.3 For whalebacks with an inclining angle αw of vided.
less than 20° the scantlings of plates and stiffeners are to
new I.3.3.1
be determined according to B.2. and B.3. respectively.
6.3 For whalebacks with an inclining angle αw of

new I.3.1.2 and I.3.2.3
less than 20° primary supporting members and sup-
porting structures are to be designed according to B.3.
6. Primary supporting members

new I.3.3.3
6.1 For primary supporting members of the struc-
ture a stress analysis has to be carried out. 7. Proof of buckling strength
Structural members' buckling strength has to be
The permissible equivalent stress is σv = 230/k [N/mm2]. proved according to Section 3, F.

new I.3.3.2
new Section 3, D.1
I - Part 1 Section 17 A Hatchways Chapter 1
GL 2012 Page 17–1

Section 17

Hatchways

A. General
2. Hatchways on lower decks and within
1. Hatchways on freeboard and superstruc- superstructures
ture decks
2.1 Coamings are not required for hatchways
1.1 The hatchways are classified according to below the freeboard deck or within weathertight
their position as defined in Section 1, H.6.7. closed superstructures unless they are required for
strength purposes.
1.2 Hatchways are to have coamings, the minimum
new C.1.9
height of which above the deck is to be as follows: 2.2 For hatch covers on lower decks and within
– in position 1: 600 mm superstructures the application of steel with ReH >
355 N/mm2 is to be agreed with GL.
– in position 2: 450 mm

new B.1.2

new C.1.1

1.3 A deviation from the requirements under 1.2 3. Definitions

may only be granted for hatchways on exposed decks
which are closed by weathertight, self tightening steel p = design load [kN/m2] for hatch covers of re-
covers. The respective exemption, in accordance with spective load cases A to D according to B.
ICLL Regulation 14-1, has to be applied for in ad- = pH for vertical loading on hatch covers
vance from the competent flag state authority.

new C.1.7 = pA for horizontal loading on edge girders
(skirt plates) of hatch covers and on coamings
1.4 Where an increased freeboard is assigned, the according to Section 16, C.2.
height of hatchway coamings according to 1.2 on the = liquid pressure p1, p2 according to Section 4,
actual freeboard deck may be as required for a super-
D.1. and pd according to Section 4, D.2.
structure deck, provided the summer freeboard is such
that the resulting draught will not be greater than that = pL for cargo loads on hatch covers according
corresponding to the minimum freeboard calculated
to Section 4, C.1.
from an assumed freeboard deck situated at a distance
equal to a standard superstructure height below the x = distance of mid point of the assessed hatch cover
actual freeboard deck. from aft end of length L or Lc, as applicable

new C.1.8
hN = superstructure standard height according to
1.5 For corrosion protection of hatch coamings ICLL
and hatch covers of bulk carriers, ore carriers and
= 1,05 + 0,01 Lc [m]; 1,8 ≤ hN ≤ 2,3
combination carriers, see Section 35, G.

new A.3

new A.2.2
Tfb = draught corresponding to the assigned sum-
1.6 For hatch covers on freeboard and superstruc- mer load line [m]
ture decks the application of steel with ReH >
355 N/mm2 is to be agreed with GL.
new D.2.1

new B.1.2 ℓ = unsupported span [m] of stiffener, to be taken

as the spacing of main girders or the distance
Note between a main girder and the edge support
Special requirements of National Administrations for hatch covers and as the spacing of coam-
regarding hatchways, hatch covers, tightening and ing stays for hatch coamings, as applicable
securing arrangements are to be observed.
a = spacing of stiffeners [m]

new A.1.3 Note
Chapter 1 Section 17 B Hatchways I - Part 1
Page 17–2 GL 2012

t = thickness of structural member [mm] 4. Corrosion additions and steel renewal

= tnet + tK
4.1 Corrosion additions
tnet = net thickness [mm]
For the scantlings of hatch covers and coamings the
tK = corrosion addition acc. to 4.1, Table 17.1 following corrosion additions tK are to be applied:

new A.3
new A.4

Table 17.1 Corrosion additions for hatch coamings and hatch covers

Application Structure tK [mm]

Weather deck hatches of container Hatch covers 1,0
ships, car carriers, paper carriers,
passenger vessels Hatch coamings according to Section 3, K.1.
Hatch covers in general 2,0
Weather exposed plating and bottom
1,5 (2,0)
Weather deck hatches of all other plating of double skin hatch covers
ship types Internal structure of double skin hatch 1,0 (1,5)
(tK-values in brackets are to be applied covers and closed box girders
to bulk carriers not covered by IACS Hatch coamings not part of the longitu-
1,5
Common Structural Rules, refer to Sec- dinal hull structure
tion 23, B.1.3) Hatch coamings part of the longitudinal
according to Section 3, K.1.
hull structure
Coaming stays and stiffeners 1,5
Hatch covers:
– top plating 1,2
Hatches within enclosed spaces
– remaining structures 1,0
Hatch coamings according to Section 3, K.1. to K.3.

B. Hatch Covers
2.1 Load case A:
1. General requirements 2.1.1 The vertical design load pH for weather deck
Primary supporting members and secondary stiffeners hatch covers is to be taken from Table 17.2. Refer to
of hatch covers are to be continuous over the breadth Fig. 17.1 for definitions of Position 1 and 2.
and length of hatch covers, as far as practical. When
new B.2.1.1
this is impractical, sniped end connections are not to
be used and appropriate arrangements are to be 2.1.2 In general, the vertical design load pH needs
adopted to provide sufficient load carrying capacity. not to be combined with load cases B and C according
to 2.2 and 2.3.
The spacing of primary supporting members parallel
to the direction of secondary stiffeners is not to exceed
new B.2.1.2
1/3 of the span of primary supporting members. When
strength calculation is carried out by FE analysis ac- 2.1.3 Where an increased freeboard is assigned, the
cording to 4.4, this requirement can be waived. design load for hatch covers according to Table 17.2
on the actual freeboard deck may be as required for a

new B.1.1 superstructure deck, provided the summer freeboard is
such that the resulting draught will not be greater than
2. Design loads that corresponding to the minimum freeboard calcu-
lated from an assumed freeboard deck situated at a
Structural assessment of hatch covers and hatch coam- distance equal to a standard superstructure height hN
ings is to be carried out according to the following below the actual freeboard deck, refer to Fig. 17.2.
design loads:

new B.2.1.3

new B.2
I - Part 1 Section 17 B Hatchways Chapter 1
GL 2012 Page 17–3

2.1.4 The vertical design load pH shall in no case pAmin = 175 kN/m2 in general for outer edge gird-
be less than the deck design load pD according to ers of hatch covers
Section 4, B.1. Instead of the deck height z the height
of hatch cover plating above baseline is then to be = 220 kN/m2 in general for hatch coamings
inserted. = 230 kN/m2 for the forward edge girder of

new B.2.1.4 the hatch 1 cover, if no fore-
castle according to Section 23,
2.1.5 The horizontal design load pA for the outer D. is arranged
edge girders (skirt plates) of weather deck hatch cov-
ers and of hatch coamings is to be determined analo- = 290 kN/m2 for the forward transverse
gously as for superstructure walls in the respective coaming of hatch 1, if no
position according to Section 16, C.2. forecastle according to Sec-
tion 23, D. is arranged

new B.2.1.5

new Section 4, B.8
For bulk carriers according to Section 23 the horizon-
tal load shall not be less than:

Table 17.2 Design load of weather deck hatches

Design load pH [kN/m2]

Position x x
≤ 0,75 0 ,75 < ≤ 1,0
Lc Lc

for Lc ≤ 100 m

on freeboard deck
9,81  x 
⋅ (4, 28 ⋅ L c + 28 ) ⋅ − 1,71 ⋅ L c + 95 
76  Lc 
9,81
⋅ (1,5 ⋅ L c + 116 )
76 upon exposed superstructure decks located at least one superstructure standard
height above the freeboard deck
9,81
⋅ (1,5 ⋅ L c + 116 )
76

for Lc > 100 m

1 on freeboard deck for type B ships according to ICLL
 x 
9 ,81 ⋅ (0,0296 ⋅ L1 + 3,04 ) ⋅ − 0 ,0222 ⋅ L1 + 1, 22 
 Lc 
on freeboard deck for ships with less freeboard than type B according to ICLL

9 ,81 ⋅ 3,5  x 
9 ,81 ⋅  (0 ,1452 ⋅ L1 − 8,52 ) ⋅ − 0 ,1089 ⋅ L1 + 9 ,89 
 Lc 
L1 = Lc, but not more than 340 m

upon exposed superstructure decks located at least one superstructure standard

height above the freeboard deck
9 ,81 ⋅ 3,5

for Lc ≤ 100 m

9,81
⋅ (1,1 ⋅ L c + 87 ,6 )
76

for Lc > 100 m

2
9 ,81 ⋅ 2 ,6

upon exposed superstructure decks located at least one superstructure standard height above the lowest Position
2 deck
9 ,81 ⋅ 2 ,1
Chapter 1 Section 17 B Hatchways I - Part 1
Page 17–4 GL 2012

2.2 Load case B: M  h 

Az = 9,81 1 + av  0,45 − 0,42 m  [kN]
( )
Where cargo is intended to be carried on hatch covers 2  b 
they are to be designed for the loads as given in Sec-
tion 4, C.1. M  hm 
If cargo with low stowage height is carried on weather
Bz = 9,81 1+ av
2
( ) 0,45+ 0,42  [kN]
b 

deck hatch covers Section 4, B.1.3 is to be observed.
B y = 2, 4 ⋅ M [kN]

new B.2.2

2.3 Load case C: av = acceleration addition according to Section 4, C.1.

Where containers are stowed on hatch covers the M = maximum designed mass of container stack [t]
following loads due to heave, pitch, and the ship's
rolling motion are to be considered, see also Fig. hm = designed height of centre of gravity of stack
17.3: above hatch cover supports [m]
2**
2**
2** 2
2 1* 1*
Freeboard deck 1 1 1

Tfb

0.25 Lc

Lc

* Reduced load upon exposed superstructure decks located at least one superstructure standard
height above the freeboard deck
** Reduced load upon exposed superstructure decks of vessels with Lc > 100 m located at least
one superstructure standard height above the lowest Position 2 deck

Fig. 17.1 Positions 1 and 2

2**
2**
2** 2**
2** 2 2
Actual freeboard deck 2 2 1*
Assumed freeboard deck ³ hN

Tfb

0.25 Lc

Lc

* Reduced load upon exposed superstructure decks located at least one superstructure standard
height above the freeboard deck
** Reduced load upon exposed superstructure decks of vessels with Lc > 100 m located at least
one superstructure standard height above the lowest Position 2 deck

Fig. 17.2 Positions 1 and 2 for an increased freeboard

I - Part 1 Section 17 B Hatchways Chapter 1
GL 2012 Page 17–5

2.4 Load case D:

Hatch covers of hold spaces intended to be filled with
liquids are to be designed for the loads specified in
Section 4, D.1. and D.2. irrespective of the filling
hm
•M height of hold spaces.

new B.2.4

A B
z
y 2.5 Load case E:
B Hatch covers, which in addition to the loads according
b z
to the above are loaded in the ship's transverse direc-
Fig. 17.3 Forces due to load case C acting on tion by forces due to elastic deformations of the ship's
hatch cover hull, are to be designed such that the sum of stresses
does not exceed the permissible values given in 3.
For M and hm those values shall be used, which are
calculated using non reduced acceleration values ac-
new B.2.5
cording to the GL Rules for Stowage and Lashing of
Containers (I-1-20), Section 3, A. When strength of 2.6 Horizontal mass forces
the hatch cover structure is assessed by FE analysis
For the design of the securing devices against shifting
according to 4.4, hm may be taken as the designed
according to 5.7 the horizontal mass forces Fh = m ⋅ a
height of centre of gravity of stack above the hatch
cover top plate. are to be calculated with the following accelerations:

b = distance between foot points [m] ax = 0,2 ⋅ g in longitudinal direction

Az, Bz, By = support forces in y- and z-direction at the
forward and aft stack corners ay = 0,5 ⋅ g in transverse direction

Values of M and hm applied for the assessment of m = sum of mass of cargo lashed on the hatch
hatch cover strength are to be shown in the drawings cover and of the hatch cover
of the hatch covers.

new B.2.6

new B.2.3.1

2.3.1 Load cases with partial loading 3. Permissible stresses and deflections
The load cases B and C are also to be considered for
3.1 Permissible stresses
partial loading which may occur in practice, e.g.
where specified container stack places are empty. The equivalent stress σv in steel hatch cover structures
The load case partial loading of container hatch cov- related to the net thickness shall not exceed 0,8 ⋅ ReH.
ers may be evaluated using a simplified approach,
where the hatch cover is loaded without the outermost For load cases B to E according to 2., the equivalent
stacks, see Fig. 17.4. stress σv related to the net thickness shall not exceed
0,9 ⋅ ReH when the stresses are assessed by means of
The design load for other cargo than containers sub-
ject to lifting forces is to be determined separately. FEM according to 4.4.

new B.2.3.3 For steels with ReH > 355 N/mm2, the value of ReH to
be applied throughout this section is to be agreed with
2.3.2 In case of container stacks secured to lashing GL but is not to be more than the minimum yield
bridges or carried in cell guides the forces acting on strength of the material.
the hatch cover may be specially considered.
For beam element calculations and grillage analysis,

new B.2.3.2 the equivalent stress may be taken as follows:

σv = σ 2 + 3 τ2 [N / mm 2 ]

σ = σb + σ n [N/mm2]

σb = bending stress [N/mm2]

σn = normal stress [N/mm2]

Fig. 17.4 Partial loading of a container hatch cover τ = shear stress [N/mm2]
Chapter 1 Section 17 B Hatchways I - Part 1
Page 17–6 GL 2012

For FEM calculations, the equivalent stress may be
new B.4.1.1

taken as follows:
Verifications of buckling strength according to
Section 3, F. are to be based on t = tnet and stresses
σ v = σ 2x − σ x ⋅ σ y + σ 2y + 3τ 2 [N/mm ]
2
corresponding to tnet applying the following safety
factors:
σx = normal stress in x-direction [N/mm2]
S = 1,25 for hatch covers when subjected to the
σy = normal stress in y-direction [N/mm2] vertical design load pH according to
2.1.
τ = shear stress in the x-y plane [N/mm2]
S = 1,1 for hatch covers when subjected to the
Indices x and y denominate axes of a two-dimensional horizontal design load pA according to
cartesian coordinate system in the plane of the consid- 2.1. as well as to load cases B to E ac-
ered structural element. cording to 2.2. through 2.5.

new B.3.1 For verification of buckling strength of plate panels
stiffened with u-type stiffeners a correction factor F1 =
3.2 Permissible deflections 1,3 may be applied.
The deflection f of weather deck hatch covers under
new B.4.1.2
the vertical design load pH shall not exceed:
For all structural components of hatch covers for
f = 0, 0056 ℓ g [m] spaces in which liquids are carried, the minimum
thickness for tanks according to Section 12, A.7. is to
be observed.
ℓg = largest span of girders [m]

new B.4.1.3

new B.3.2
4.2 Hatch cover supports

Note Supports and stoppers of hatch covers are in general to

be so arranged that no constraints due to hull deforma-
Where hatch covers are arranged for carrying con- tions occur in the hatch cover structure and at stoppers
tainers and mixed stowage is allowed, i.e. a 40' - respectively, see also load case E according to 2.5.
container on stowages places for two 20' - contain-
Deformations due to the design loads according to 2.
ers, the deflections of hatch covers have to be particu-
between coaming and weathertight hatch covers, as well
larly observed. Further the possible contact of de-
flected hatch covers with in hold cargo has to be ob- as between coaming and covers for hold spaces in which
served. liquids are carried, shall not lead to leakiness, refer to 6.
For bulk carriers according to Section 23 force trans-

new B.3.2 Note
mitting elements are to be fitted between the hatch
cover panels with the purpose of restricting the rela-
3.3 Where hatch covers are made of aluminium tive vertical displacements. However, each panel has
alloys, Section 2, D. is to be observed. For permissible to be assumed as independently load-bearing.
deflections 3.2 applies.
If two or more deck panels are arranged on one hatch,

new B.3.3 clearances in force transmitting elements between
panels have generally to be observed.
3.4 The permissible stresses specified under 3.1
apply to primary girders of symmetrical cross section. Stiffness of securing devices, where applicable, and
For unsymmetrical cross sections, e.g. -sections, clearances are to be considered.
equivalence in regard to strength and safety is to be

new B.4.2
proved, see also Section 3, L.

new B.3.4 4.3 Strength calculations for beam and girder
grillages
4. Strength calculation for hatch covers Cross-sectional properties are to be determined consid-
ering the effective breadth according to Section 3, E.
4.1 General Cross sectional areas of stiffeners parallel to the girder
Calculations are to be based on net thickness web within the effective breadth can be included, see
Section 3, F.2.2.
t net = t − t K Special calculations may be required for determining
the effective breadth of one-sided or non-symmetrical
The tK values used for calculation have to be indicated flanges.
in the drawings.
I - Part 1 Section 17 B Hatchways Chapter 1
GL 2012 Page 17–7

The effective cross sectional area of plates is not to be  σ 

less than the cross sectional area of the face plate. = 1, 0 + 2,5  − 0, 64  ≥ 1,0
R 
 eh 
The effective width of flange plates under compres-
sion with stiffeners perpendicular to the girder web is for p from deck design load pD or liquid
to be determined according to Section 3, F.2.2. pressure p1, p2 and pd

new B.4.3.1
σ = normal stress [N/mm2] of main girders
In way of larger cutouts in girder webs it may be re-
quired to consider second order bending moments. For flange plates under compression sufficient buck-
ling strength according to Section 3, F. is to be verified.

new B.4.3.2

new B.5.1.1.1
4.4 FEM calculations For hatch covers subject to wheel loading plate thick-
For strength calculations of hatch covers by means of ness shall not be less than according to Section 7, B.2.
finite elements, the cover geometry shall be idealised
new B.5.1.1.2
as realistically as possible. Element size shall be ap-
propriate to account for effective breadth. In no case 5.1.2 Lower plating of double skin hatch covers
element width shall be larger than stiffener spacing. In and box girders
way of force transfer points, cutouts and one-sided or
non-symmetrical flanges the mesh has to be refined The thickness is to be obtained from the calculation
where applicable. according to 4. under consideration of permissible
stresses according to 3.1.
The ratio of element length to width shall not exceed 4.
The thickness shall not be less than the larger of the
The element height of girder webs shall not exceed following values:
one-third of the web height.
t = 6,5 · a + tK [mm]
Stiffeners, supporting plates against lateral loads, have
to be included in the idealization. tmin = 5,0 + tK [mm]
Buckling stiffeners may be disregarded for the stress
calculation. The lower plating of hatch covers for spaces in which
liquids are carried is to be designed for the liquid

new B.4.4 pressure and the thickness is to be determined accord-
ing to 5.1.1.
5. Scantlings
new B.5.1.2
5.1 Hatch cover plating 5.2 Main girders
5.1.1 Top plating Scantlings of main girders are obtained from the cal-
culation according to 4. under consideration of per-
The thickness of the hatch cover top plating is to be missible stresses according to 3.1.
obtained from the calculation according to 4. under
consideration of permissible stresses according to 3.1. For all components of main girders sufficient safety
against buckling shall be verified according to Section
However, the thickness shall not be less than the larg- 3, F. For biaxially compressed flange plates this is to
est of the following values: be verified within the effective widths according to
Section 3, F.2.2.
t = t net + t K [mm]
At intersections of flanges from two girders, notch
p stresses have to be observed.
= cp ⋅ 16, 2 ⋅ a + tK
R eH The thickness of main girder webs shall not be less
than:

t = 10 ⋅ a + t K [mm] t = 6,5 · a + tK [mm]

t min = 6, 0 + t K [mm] tmin = 5,0 + tK [mm]

 σ 
new B.5.2.1
cp = 1,5 + 2,5  − 0, 64  ≥ 1,5
R 
 eh  For hatch covers of bulk carriers according to Section
23 the ratio of flange width to web height shall not
for p = pH or cargo load pL
exceed 0,4, if the unsupported length of the flange
between two flange supports of main girders is larger
Chapter 1 Section 17 B Hatchways I - Part 1
Page 17–8 GL 2012

than 3,0 m. The ratio of flange outstand to flange 104

thickness shall not exceed 15. Wnet = ⋅ a ⋅ ℓ 2 ⋅ p [cm3 ]
R eH

new B.5.2.2
10 ⋅ a ⋅ ℓ ⋅ p
Asnet = [cm 2 ]
5.3 Edge girders (Skirt plates) R eH

5.3.1 Scantlings of edge girders are obtained from The net section modulus of the stiffeners is to be de-
the calculations according to 4 under consideration of termined based on an attached plate width assumed
permissible stresses according to 3.1. equal to the stiffener spacing.

new B.5.3.1 For flat bar stiffeners and buckling stiffeners, the ratio
h/tw is to be not greater than 15 · k0,5, where:
For all components of edge girders sufficient safety
against buckling shall be verified according to Section h = height of the stiffener
3, F. tw = net thickness of the stiffener

new B.5.3.2 k = 235/ReH
The thickness of the outer edge girders exposed to
wash of sea shall not be less than the largest of the Stiffeners parallel to main girder webs and arranged
following values: within the effective breadth according to Section 3, E.
shall be continuous at crossing transverse girders and
t = t net + t K [mm] may be regarded for calculating the cross sectional
properties of main girders. It is to be verified that the
pA resulting combined stress of those stiffeners, induced
= 16, 2 ⋅ a + tK by the bending of main girders and lateral pressures,
R eH does not exceed the permissible stress according to
3.1.
t = 8,5 ⋅ a + t K [mm]
For hatch cover stiffeners under compression suffi-
t min = 5, 0 + t K [mm] cient safety against lateral and torsional buckling
according to Section 3, F. is to be verified.

new B.5.3.1
For hatch covers subject to wheel loading stiffener
5.3.2 The stiffness of edge girders of weather deck scantlings are to be determined by direct calculations
hatch covers is to be sufficient to maintain adequate under consideration of the permissible stresses accord-
sealing pressure between securing devices. The mo- ing to 3.1.
ment of inertia of edge girders is not to be less than:
new B.5.4
4 4
I = 6⋅q⋅s [cm ] 5.5 Hatch cover supports
q = packing line pressure [N/mm], minimum 5.5.1 For the transmission of the support forces
5 N/mm resulting from the load cases specified in 2.1 – 2.6,
s = spacing [m] of securing devices supports are to be provided which are to be designed
such that the nominal surface pressures in general do

new B.5.3.1 not exceed the following values:
5.3.3 For hatch covers of spaces in which liquids p n max = d ⋅ p n [N / mm 2 ]
are carried, the packing line pressure shall also be
ensured in case of hatch cover loading due to liquid
pressure. d = 3,75 – 0,015 L

new B.5.3.3 dmax = 3,0
dmin = 1,0 in general
5.4 Hatch cover stiffeners
The net section modulus Wnet and net shear area Asnet = 2,0 for partial loading conditions (see 2.3.1.)
of uniformly loaded hatch cover stiffeners constraint pn = see Table 17.3
at both ends shall not be less than:
For metallic supporting surfaces not subjected to rela-
tive displacements the following applies:

p n max = 3 ⋅ pn [N / mm 2 ]
I - Part 1 Section 17 B Hatchways Chapter 1
GL 2012 Page 17–9

Where large relative displacements of the supporting
new B.5.5.6

surfaces are to be expected, the use of material having
low wear and frictional properties is recommended. 5.5.7 For substructures and adjacent structures of

new B.5.5.1 supports subjected to horizontal forces Ph, a fatigue
strength analysis is to be carried out according to
Section 20 by using the stress spectrum B and apply-
Table 17.3 Permissible nominal surface pres-
sure pn ing the horizontal force Ph.

new B.5.5.7
pn [N/mm2]
when loaded by 5.6 Securing of weather deck hatch covers

Support vertical horizontal

force force 5.6.1 Securing devices between cover and coaming
material and at cross-joints are to be provided to ensure
(on stoppers)
weathertightness. Sufficient packing line pressure is to
Hull structural be maintained. The packing line pressure is to be
25 40
steels specified in the drawings.
hardened steels 35 50 Securing devices shall be appropriate to bridge dis-
plastic materials placements between cover and coaming due to hull
50 –– deformations.
on steel

new B.5.6.1
5.5.2 Drawings of the supports shall be submitted.
In the drawings of the supports the permitted maxi- 5.6.2 Securing devices are to be of reliable con-
mum pressure given by the material manufacturer struction and effectively attached to the hatchway
related to long time stress is to be specified. coamings, decks or covers. Individual securing de-

new B.5.5.2 vices on each cover are to have approximately the
same stiffness characteristics.
5.5.3 If necessary, sufficient abrasive strength may

new B.5.6.1
be shown by tests demonstrating an abrasion of sup-
port surfaces of not more than 0,3 mm per one year in
service at a total distance of shifting of 15 000 m/ 5.6.3 Where rod cleats are fitted, resilient washers
year. or cushions are to be incorporated.

new B.5.5.3
new B.5.6.2

5.5.4 The substructures of the supports have to be 5.6.4 Where hydraulic cleating is adopted, a posi-
of such a design, that a uniform pressure distribution tive means is to be provided to ensure that it remains
is achieved. mechanically locked in the closed position in the event
of failure of the hydraulic system.

new B.5.5.4

new B.5.6.3
5.5.5 Irrespective of the arrangement of stoppers,
the supports shall be able to transmit the following 5.6.5 Sufficient number of securing devices is to be
force Ph in the longitudinal and transverse direction: provided at each side of the hatch cover considering
the requirements of 5.3.2. This applies also to hatch
Pv covers consisting of several parts.
Ph = µ ⋅
d
new B.5.6.1

Pv = vertical supporting force 5.6.6 Specifications of materials of securing de-

vices and their weldings are to be shown in the draw-
µ = frictional coefficient ings of the hatch covers.
= 0,5 for steel on steel
new B.5.6.1

= 0,35 for non-metallic, low-friction support 5.6.7 The net cross-sectional area of the securing
materials on steel devices is not to be less than:

new B.5.5.5
A = 0, 28 ⋅ q ⋅ s ⋅ k ℓ [cm 2 ]
5.5.6 Supports as well as the adjacent structures
and substructures are to be designed such that the q = packing line pressure [N/mm], minimum
permissible stresses according to 3.1 are not exceeded. 5 N/mm
Chapter 1 Section 17 B Hatchways I - Part 1
Page 17–10 GL 2012

s = spacing between securing devices [m], not to 5.7 Hatch cover stoppers
be taken less than 2 m
Hatch covers shall be sufficiently secured against
e shifting.
 235 
kℓ =   Stoppers are to be provided for hatch covers on which
 R eH  cargo is carried as well as for hatch covers, which
edge girders have to be designed for pA > 175 kN/m2
ReH is not to be taken greater than 0,70 Rm. according to 2.1.5.
e = 0,75 für ReH > 235 N/mm2 Design forces for the stoppers are obtained from the
loads according to 2.1.5 and 2.6.
= 1,00 für ReH ≤ 235 N/mm2
The permissible stress in stoppers and their substruc-
Rods or bolts are to have a net diameter not less than tures in the cover and of the coamings is to be deter-
19 mm for hatchways exceeding 5 m2 in area. mined according to 3.1.
Securing devices of special design in which significant The provisions in 5.5 are to be observed.
bending or shear stresses occur may be designed ac-

new B.5.7
cording to 5.6.8. As load the packing line pressure q
multiplied by the spacing between securing devices s 5.8 Cantilevers, load transmitting elements
is to be applied.

new B.5.6.4 5.8.1 Cantilevers and load transmitting elements
which are transmitting the forces exerted by hydraulic
cylinders into the hatchway covers and the hull are to
5.6.8 The securing devices of hatch covers, on
be designed for the forces stated by the manufacturer.
which cargo is to be lashed, are to be designed for the
The permissible stresses according to 3.1 are not to be
lifting forces according to 2.3., load case C, refer to
exceeded.
Fig. 17.5. Unsymmetrical loadings, which may occur
in practice, are to be considered. Under these loadings
new B.5.8.1
the equivalent stress in the securing devices is not to
exceed: 5.8.2 Structural members subjected to compressive
stresses are to be examined for sufficient safety
150 against buckling, according to Section 3, F.
σv = [N / mm 2 ]
kℓ
new B.5.8.2
5.8.3 Particular attention is to be paid to the struc-

new B.5.6.5 tural design in way of locations where loads are intro-
duced into the structure.
5.6.9 Securing devices of hatch covers for spaces
in which liquids are carried shall be designed for the
new B.5.8.3
lifting forces according to 2.4., load case D.
5.9 Container foundations on hatch covers

new B.5.6.6
Container foundations and their substructures are to be
5.6.10 Cargo deck hatch covers consisting of several designed for the loads according to 2., load cases B
parts have to be secured against accidental lifting. and C, respectively, applying the permissible stresses
according to 3.1.

new B.5.6.7

new B.5.9

6. Weather tightness of hatch covers

For weather deck hatch covers packings are to be
provided, for exceptions see 6.2.

new D.1
AZ AZ AZ AZ AZ
BZ BZ BZ BZ BZ
6.1 Packing material

6.1.1 The packing material is to be suitable for all

Lifting Force expected service conditions of the ship and is to be
compatible with the cargoes to be transported.
Fig. 17.5 Lifting forces at a hatch cover The packing material is to be selected with regard to
dimensions and elasticity in such a way that expected
deformations can be carried. Forces are to be carried
by the steel structure only.
I - Part 1 Section 17 B Hatchways Chapter 1
GL 2012 Page 17–11

The packings are to be compressed so as to give the Where a hatch is covered by several hatch cover pan-
necessary tightness effect for all expected operating els the clear opening of the gap in between the panels
conditions. shall be not wider than 50mm.
Special consideration shall be given to the packing The labyrinths and gaps between hatch cover panels
arrangement in ships with large relative movements shall be considered as unprotected openings with
between hatch covers and coamings or between hatch respect to the requirements of intact and damage sta-
cover sections. bility calculations.

new D.2.1 With regard to drainage of cargo holds and the neces-
sary fire-fighting system reference is made to the GL
6.1.2 If the requirements in 6.2 are fulfilled the Rules for Machinery Installations (I-1-2), Sections 11
weather tightness can be dispensed with. and 12.

new D.2.2 Bilge alarms should be provided in each hold fitted
with non-weathertight covers.
6.2 Non-weathertight hatch covers
Furthermore, the requirements for the carriage of
6.2.1 Upon request and subject to compliance with dangerous goods are to be complied with, refer to
the following conditions the fitting of weather tight Chapter 3 of IMO MSC/Circ. 1087.
gaskets according to 6.1 may be dispensed with for
new D.3.1
hatch covers of cargo holds soley for the transport of
containers: 6.2.2 Securing devices

new D.3.1 In the context of 6.2 an equivalence to 5.6 can be
considered subject to:
6.2.1.1 The hatchway coamings shall be not less than
600 mm in height. – the proof that in accordance with 2.3 (load case
C) securing devices are not to be required and

new D.3.1
additionally
6.2.1.2 The exposed deck on which the hatch covers – the transverse cover guides are effective up to a
are located is situated above a depth H(x). height hE above the cover supports, see Fig.
H(x) is to be shown to comply with the following 17.6. The height hE shall not be less than the
calculated criteria: greater of the following:
H(x) ≥ Tfb + f b + h [m] hE = 1, 75 ⋅ 2 ⋅ e ⋅ s [mm]
Tfb = draught corresponding to the assigned sum- hEmin = height of the face plate [mm] + 150
mer load line[m]
where
fb = minimum required freeboard determined in
accordance with ICLL [m] e = largest distance of the cover guides
from the longitudinal face plate [mm]
x
h = 4,6 m for ≤ 0, 75 s = total clearance [mm]
L
with
x
= 6,9 m for > 0, 75 10 ≤ s ≤ 40
L

new D.3.1 The transverse guides and their substructure are to be
dimensioned in accordance with the loads given in 2.6
6.2.1.3 Labyrinths or equivalents are to be fitted acting at the position hE using the equivalent stress
proximate to the edges of each panel in way of the level σv = ReH [N/mm2].
coamings. The clear profile of these openings is to be
kept as small as possible.
new D.3.2
Chapter 1 Section 17 C Hatchways I - Part 1
Page 17–12 GL 2012

hE

s e

Fig. 17.6 Height of transverse cover guides

6.3 Drainage arrangements 6.4.2 Upon completion of the hatchway cover

system trials for proper functioning are to be carried
6.3.1 If drain channels are provided inside the line out in presence of the Surveyor.
of gasket by means of a gutter bar or vertical exten-

new D.5.2
sion of the hatch side and end coaming, drain open-
ings are to be provided at appropriate positions of the
drain channels.

new D.4.2 C. Hatch Coamings and Girders

6.3.2 Drain openings in hatch coamings are to be 1. General

arranged with sufficient distance to areas of stress
concentration (e.g. hatch corners, transitions to crane 1.1 Hatch coamings which are part of the longi-
posts). tudinal hull structure are to be designed according to
Section 5. For structural members welded to coamings

new D.4.2
and for cutouts in the top of coaming sufficient fatigue
strength according to Section 20 is to be verified.
6.3.3 Drain openings are to be arranged at the ends
of drain channels and are to be provided with non- In case of transverse coamings of ships with large
return valves to prevent ingress of water from the deck openings Section 5, F. is to be observed.
outside. It is unacceptable to connect fire hoses to the
drain openings for this purpose.
new C.1.5

new D.4.2
1.2 Coamings which are 600 mm or more in
height are to be stiffened by a horizontal stiffener.
6.3.4 Cross-joints of multi-panel covers are to be
provided with efficient drainage arrangements. Where the unsupported height of a coaming exceeds
1,2 m additional stiffeners are to be arranged.

new D.4.1
Additional stiffeners may be dispensed with if this is
6.3.5 If a continuous outer steel contact between justified by the ship's service and if sufficient strength
cover and ship structure is arranged, drainage from the is verified (e.g. in case of container ships).
space between the steel contact and the gasket is also
to be provided for.
new C.1.12

new D.4.2 Stiffeners of hatch coamings are to be continuous over
the breadth and length of hatch coamings.
6.4 Tightness test, trials

new C.1.13
6.4.1 The self-tightening steel hatch covers on Longitudinal hatchway coamings are to be adequately
weather decks and within open superstructures are to supported by stays or brackets.
be hose tested. The water pressure should not be less
than 2 bar and the hose nozzle should be held at a dis-
new C.1.8
tance of not more than 1,5 m from the hatch cover to
be tested. The nozzle diameter should not be less than Adequate safety against buckling is to be proved for
12 mm. During frost periods equivalent tightness tests longitudinal coamings which are part of the longitudi-
may be carried out to the satisfaction of the Surveyor. nal hull structure.

new D.5.1
new C.1.7
I - Part 1 Section 17 C Hatchways Chapter 1
GL 2012 Page 17–13

1.3 Hatchway coamings which are exposed to the
new C.2.1.1

wash of sea are to be designed for the loads according
to B.2.1.5 For grab operation see also Section 23, B.9.1.

new C.2.1.2
1.4 On ships carrying cargo on deck, such as
timber, coal or coke, the stays are to be spaced not The thickness of weather deck hatch coamings, which
more than 1,5 m apart. For containers on deck, see are part of the longitudinal hull structure, is to be de-
also Section 21, G.3.4. signed analogously to side shell plating according to
Section 6.

new C.1.10

new C.2.1.1
1.5 Coaming girders are to extend to the lower
edge of the deck transverses; they are to be flanged or 2.2 Coaming stays
fitted with face bars or half-round bars.

new C.1.11 2.2.1 Coaming stays are to be designed for the
loads and permissible stresses according to B.
1.6 The connection of the coamings to the deck
new C.2.2.1
at the hatchway corners is to be carried out with spe-
cial care. For bulk carriers, see also Section 23, B.9. 2.2.2 The net section modulus of coaming stays of
For rounding of hatchway corners, see also Section 7, coamings having a height of hs < 1,6 m and which are
A.3. to be designed for the load pA, shall not be less than:

new C.1.14 526
Wnet = ⋅ e ⋅ h s2 ⋅ pA [cm3 ]
R eH
1.7 For hatch way coamings which are designed
on the basis of strength calculations as well as for
hatch girders, cantilevers and pillars, see Section 10. e = spacing of coaming stays [m]

new C.1.5 Coaming stays of coamings having a height of 1,6 m
or more are to be designed using direct calculations.
1.8 Longitudinal hatch coamings with a length For the calculation of Wnet the effective breadth of the
exceeding 0,1 ⋅ L are to be provided with tapered coaming plate shall not be larger than the effective
brackets or equivalent transitions and a corresponding plate width according to Section 3, F.2.
substructure at both ends. At the end of the brackets
they are to be connected to the deck by full penetra-
new C.2.2.2
tion welds of minimum 300 mm in length.
Coaming stays are to be supported by appropriate

new C.1.6 substructures. Underdeck structures are to be designed
under consideration of permissible stresses according
2. Scantlings to B.

new C.1.9
2.1 Plating
Face plates may only be included in the calculation if
The thickness of weather deck hatch coamings shall an appropriate substructure is provided and welding
not be less than the larger of the following values: ensures an adequate joint.
t = t net + t K [mm]
new C.2.2.2

2.2.3 The web thickness of coaming stays at its

pA lower end shall not be less than:
= c⋅a + tK
R eH
t w = t net + t K [mm]
L
t min = 6 + + t K [mm] 2 e ⋅ hs ⋅ pA
100 = ⋅ + tK
R eH hw
c = 16.4 for bulk carrier according to Section 23
hw = web height of coaming stay at its lower end
c = 14.6 for all other ships
[m]
L need not be taken greater than 300 m
Webs are to be connected to the decks by fillet welds
tmin = 9,5 + tK [mm] for bulk carrier according to on both sides with a throat thickness of a = 0,44 ⋅ tw.
Section 23 For toes of stay webs within 0,15 ⋅ hw the throat thick-
ness is to be increased to a = 0,7 ⋅ tw for tw ≤ 10 mm.
Chapter 1 Section 17 D Hatchways I - Part 1
Page 17–14 GL 2012

For tw > 10 mm deep penetration double bevel welds 1.2 If not bolted watertight, they are to be of
are to be provided in this area. substantial steel construction with bayonet joints or
screws. The covers are to be hinged or to be perma-

new C.2.2.3 nently attached to the deck by a chain.
2.2.4 For coaming stays, which transfer friction
forces at hatch cover supports, sufficient fatigue 1.3 Openings in freeboard decks other than
strength according to Section 20 is to be verified, refer hatchways and machinery space openings, may only
also to B.5.5. be arranged in weathertight closed superstructures or
deckhouses or in weathertight closed companionways

new C.2.2.4 of the same strength

2.3 Horizontal stiffeners

1.4 Companionways or access hatches on ex-
The stiffeners shall be continuous at the coaming stays. posed parts of freeboard decks, on decks of closed
superstructures and in special cases on the deck of
For stiffeners with both ends constraint the elastic net
deckhouses are to be of solid construction. The height
section modulus Wnet and net shear area As net shall of the doorway sills is to be 600 mm above decks in
not be less than: pos. 1 and 450 mm (hatches) and 380 mm (doors)
respectively above decks in pos. 2.
c ⋅ a ⋅ ℓ 2 ⋅ pA
Wnet = [cm3 ]
f p ⋅ R eH
1.5 The doors of the companionways are to be
capable of being operated and secured from both
10 ⋅ a ⋅ ℓ ⋅ pA sides. They are to be closed weathertight by rubber
Asnet = [cm 2 ] sealings and toggles.
R eH

c = 75 for bulk carriers according to Section 23 1.6 Access hatchways shall have a clear width of
at least 600 ⋅ 600 mm.
c = 83 for all other ships

fp = ratio of plastic and elastic section modulus
new Section 21, P.1.8

= 1,0 for ships other than bulk carrier according

1.7 Weathertight small hatches in Load Line Po-
to Section 23
sition 1 and 2 according to ICLL shall be generally
Rm equivalent to the international standard ISO 5778.
fpmax =
R eH
new Section 21, P.1.9

= 1,16 in the absence of more precise evaluation

1.8 For special requirements for strength and
For sniped stiffeners at coaming corners section securing of small hatches on the exposed fore deck,
modulus and shear area at the fixed support have to be see 2.
increased by 35 %.
The thickness of the coaming plate at the sniped stiff-
new Section 21, P.1.10
ener end shall not be less than according to Section 3,
D.3.
1.9 According to the IACS Unified Interpretation
Horizontal stiffeners on hatch coamings, which are part SC 247 the following applies to securing devices of
of the longitudinal hull structure, are to be designed emergency escape hatches:
analogously to longitudinals according to Section 9.

new C.2.3 – Securing devices shall be of a type which can be
opened from both sides.

– The maximum force needed to open the hatch

D. Smaller Openings and Hatches cover should not exceed 150 N.

1. Miscellaneous openings in freeboard and

– The use of a spring equalizing, counterbalance
superstructure decks
or other suitable device on the ring side to
reduce the force needed for opening is accept-
1.1 Manholes and small flush deck hatches in able.
decks in pos. 1 and 2 or in open superstructures are to
be closed watertight.
new Section 21, P.1.11
I - Part 1 Section 17 D Hatchways Chapter 1
GL 2012 Page 17–15

2. Strength and securing of small hatches on Primary Secondary

Cover
the exposed fore deck stiffeners stiffeners
Nominal size plate
[mm × mm] thickness Flatbar [mm × mm];
2.1 General [mm] number
2.1.1 The strength of, and securing devices for, 630 × 630 8 –– ––
small hatches fitted on the exposed fore deck over the
forward 0,25 L are to comply with the following re- 630 × 830 8 100 × 8; 1 ––
quirements. 8 ––
830 × 630 100 × 8; 1

new Section 21, P.2.1.1
830 × 830 8 100 × 10; 1 ––
2.1.2 Small hatches in this context are hatches de- 1030 × 1030 8 120 × 12; 1 80 × 8; 2
signed for access to spaces below the deck and are capa-
ble to be closed weathertight or watertight, as applicable. 1330 × 1330 8 150 × 12; 2 100 × 10; 2
Their opening is normally 2,5 square meters or less.
For ships with L < 80 m the cover scantlings may be

new Section 21, P.2.1.2 reduced by the factor
0,11 ⋅ L ≥ 0, 75
2.1.3 For securing devices of emergency escape
hatches see 1.9. Additionally the hatches are to be
fitted with central locking devices according to 2.4.1
(method C). Regulations 2.5.3 and 2.6 need not be
complied with.
Stiffeners, where fitted, are to be aligned with the

new Section 21, P.2.1.3 metal-to-metal contact points, required in 2.5.1, see
Fig. 17.7. Primary stiffeners are to be continuous. All
2.2 Application stiffeners are to be welded to the inner edge stiffener,
For ships on the exposed deck over the forward see Fig. 17.8.
0,25 L, applicable to all types of sea going ships
– that are contracted for construction on or after
1st January 2004 1 and
new Section 21, P.2.3.1

– where the height of the exposed deck in way of

the hatch is less than 0,1 L or 22 m above the
summer load waterline, whichever is the lesser 2.3.2 The upper edge of the hatchway coamings is

new Section 21, P.2.2 to be suitably reinforced by a horizontal section, nor-
mally not more than 170 mm to 190 mm from the
2.3 Strength upper edge of the coamings.

2.3.1 For small rectangular steel hatch covers, the

plate thickness, stiffener arrangement and scantlings
are to be in accordance with Table 17.4 and Fig. 17.7.
new Section 21, P.2.3.2

Table 17.4 Scantlings for small steel hatch covers

on the fore deck
2.3.3 For small hatch covers of circular or similar
shape, the cover plate thickness and reinforcement is
to be specially considered.

new Section 21, P.2.3.3

2.3.4 For small hatch covers constructed of materi-

als other than steel, the required scantlings are to pro-
vide equivalent strength.

1 For ships contracted for construction prior to 1st July 2007

refer to IACS UR S26, para. 3.
new Section 21, P.2.3.4
Chapter 1 Section 17 D Hatchways I - Part 1
Page 17–16 GL 2012

Nominal size 630 x 630 Nominal size 630 x 830 Nominal size 830 x 630

Nominal size 830 x 830 Nominal size 1030 x 1030 Nominal size 1330 x 1330

Hinge Primary stiffener

Securing device / metal to metal contact Secondary stiffener

Fig. 17.7 Arrangement of stiffeners

M20

1 : butterfly nut

2 : bolt
3 : pin 5 (min. 16 mm) 6
1
4 : center of pin
5 : fork (clamp) plate
6 : hatch cover
9
7 : gasket
2
7
8 : hatch coaming
: bearing pad welded on the bracket
20

9
of a toggle bolt for metal to metal
contact 3
10 : stiffener 4

11 : inner edge stiffener 8 11 10

Fig. 17.8 Example of a primary securing method

I - Part 1 Section 17 E Hatchways Chapter 1
GL 2012 Page 17–17

2.4 Primary securing devices 2.5.5 On small hatches located between the main
hatches, for example between Nos. 1 and 2, the hinges
2.4.1 Small hatches located on exposed fore deck are to be placed on the fore edge or outboard edge,
subject to the application according to 2.2 are to be whichever is practicable for protection from green
fitted with primary securing devices such that their water in beam sea and bow quartering conditions.
hatch covers can be secured in place and weathertight
by means of a mechanism employing any one of the
new Section 21, P.2.5.5
following methods:
2.6 Secondary securing device
– method A: butterfly nuts tightening onto
forks (clamps) Small hatches on the fore deck are to be fitted with an
independent secondary securing device e.g. by means
– method B: quick acting cleats
of a sliding bolt, a hasp or a backing bar of slack fit,
– method C: central locking device which is capable of keeping the hatch cover in place,
even in the event that the primary securing device

new Section 21, P.2.4.1 became loosened or dislodged. It is to be fitted on the
side opposite to the hatch cover hinges.
2.4.2 Dogs (twist tightening handles) with wedges Fall arresters against accidental closing are to be pro-
are not acceptable. vided.

new Section 21, P.2.4.2

new Section 21, P.2.6

2.5 Requirements for primary securing

2.5.1 The hatch cover is to be fitted with a gasket E. Engine and Boiler Room Hatchways
of elastic material. This is to be designed to allow a
metal to metal contact at a designed compression and 1. Deck openings
to prevent over-compression of the gasket by green
sea forces that may cause the securing devices to be
loosened or dislodged. The metal-to-metal contacts are 1.1 The openings above engine rooms and boiler
to be arranged close to each securing device in accor- rooms should not be larger than necessary. In way of
dance with Fig. 17.7 and of sufficient capacity to these rooms sufficient transverse strength is to be
withstand the bearing force. ensured.

new Section 21, P.2.5.1
new Section 21, Q.1.1

2.5.2 The primary securing method is to be de- 1.2 Engine and boiler room openings are to be
signed and manufactured such that the designed com- well rounded at their corners, and if required, to be
pression pressure is achieved by one person without provided with strengthenings, unless proper distribu-
the need of any tools. tion of the longitudinal stresses is ensured by the side

new Section 21, P.2.5.2 walls of superstructures or deckhouses. See also
Section 7, A.3.
2.5.3 For a primary securing method using butter-
new Section 21, Q.1.2
fly nuts, the forks (clamps) are to be of robust design.
They are to be designed to minimize the risk of butter-
fly nuts being dislodged while in use; by means of 2. Engine and boiler room casings
curving the forks upward, a raised surface on the free
end, or a similar method. The plate thickness of un-
2.1 Engine and boiler room openings on weather
stiffened steel forks is not to be less than 16 mm. An
decks and inside open superstructures are to be pro-
example arrangement is shown in Fig. 17.8.
tected by casings of sufficient height.

new Section 21, P.2.5.3

new Section 21, Q.2.1
2.5.4 For small hatch covers located on the ex-
posed deck forward of the foremost cargo hatch, the 2.2 The height of casings on the weather deck of
hinges are to be fitted such that the predominant direc- ships with full scantling draught is to be not less than
tion of green sea will cause the cover to close, which 1,8 m where L does not exceed 75 m, and not less
means that the hinges are normally to be located on than 2,3 m where L is 125 m or more. Intermediate
the fore edge. values are to be determined by interpolation.

new Section 21, P.2.5.4
new Section 21, Q.2.2

Chapter 1 Section 17 E Hatchways I - Part 1
Page 17–18 GL 2012

2.7 The coaming plates are to be extended to the

2.3 The scantlings of stiffeners, plating and cov- lower edge of the deck beams.
ering of exposed casings are to comply with the re-
new Section 21, Q.2.7
quirements for superstructure end bulkheads and for
deckhouses according to Section 16, C.
3. Doors in engine and boiler room casings

new Section 21, Q.2.3
3.1 The doors in casings on exposed decks and
2.4 Inside open superstructures the casings are to within open superstructures are to be of steel, well
be stiffened and plated according to Section 16, C., as stiffened and hinged, and capable of being closed from
for an aft end bulkhead. both sides and secured weathertight by toggles and

new Section 21, Q.2.4 rubber sealings.

new Section 21, Q.3.1
2.5 The height of casings on superstructure decks
is to be at least 760 mm. The thickness of their plating Note
may be 0,5 mm less than derived from 2.3, and the
stiffeners are to have the same thickness and a depth For ships with reduced freeboard (B-minus) or tanker free-
of web of 75 mm, being spaced at 750 mm. board (A), Regulation 26 (1) of ICLL is to be observed.

new Section 21, Q.2.5
new Section 21, Q.3.1 Note

3.2 The doors are to be at least of the same

2.6 The plate thickness of engine and boiler room strength as the casing walls in which they are fitted.
casings below the freeboard deck or inside closed
superstructures is to be 5 mm, and 6,5 mm in cargo
new Section 21, Q.3.2
holds; stiffeners are to have at least 75 mm web depth,
and the same thickness as the plating, when being 3.3 The height of the doorway sills is to be
spaced at 750 mm. 600 mm above decks in pos. 1 and 380 mm above
decks in pos. 2.

new Section 21, Q.2.6

new Section 21, Q.3.3
I - Part 1 Section 18 A Equipment Chapter 1
GL 2012 Page 18–1

Section 18

Equipment

A. General
For the location of windlasses on tankers, see Section
24, A.9.
1. The equipment of anchors and chain cables as
well as the recommended equipment of wires and ropes
new A.2.3
is to be determined from Table 18.2 in accordance with
the equipment numeral Z1 or Z2, respectively. 3. For ships having the navigation notation
RSA(20) or RSA(50) affixed to their character of

new A.1.2 classification, the equipment may be determined as for
one numeral range lower than required in accordance
Note with the equipment numeral Z1 or Z2, respectively.
The anchoring equipment required by this Section is
new A.1.3
intended of temporary mooring of a vessel within a
harbour or sheltered area when the vessel is awaiting 4. When determining the equipment for ships
berth, tide, etc. having the navigation notation RSA(SW) affixed to
The equipment is, therefore, not designed to hold a their character of classification, the provisions of Sec-
ship off fully exposed coasts in rough weather or to tion 30, E. are to be observed.
stop a ship which is moving or drifting. In this condi-
new A.2.4
tion the loads on the anchoring equipment increase to
such a degree that its components may be damaged or 5. When determining the equipment for tugs,
lost owing to the high energy forces generated, par- Section 25, G. is to be observed.
ticularly in large ships.

new A.2.5
The anchoring equipment required by this Section is
designed to hold a ship in good holding ground in When determining the equipment of barges and pon-
conditions such as to avoid dragging of the anchor. In toons, Section 31, G. is to be observed.
poor holding ground the holding power of the anchors

new A.2.6
will be significantly reduced.
The equipment numeral formula for anchoring equip- 6. Ships built under survey of GL and which are
ment required under this Section is based on an as- to have the mark  stated in their Certificate and in
sumed current speed of 2,5 m/sec, wind speed of the Register Book shall be equipped with anchors and
25 m/sec and a scope of chain cable between 6 and chain cables complying with the Rules for Materials
10, the scope being the ratio between length of chain and having been tested on approved machines in the
paid out and water depth. presence of a Surveyor.
It is assumed that under normal circumstances a ship
I-0, Section 2, Table 2.1
will use only one bow anchor and chain cable at a
time.
7. For ships having three or more propellers, a

new A.1.4 reduction of the weight of the bower anchors and the
chain cables may be considered.
2. Every ship is to be equipped with at least one
anchor windlass. Note

new A.1.1 Seagoing ships navigating on inland waters and rivers
are to have anchor equipment also complying with the
Windlasses and chain stoppers, if fitted, are to comply Regulations of the competent authorities.; e.g for ships
with the GL Rules for Machinery Installations (I-1-2), navigating on the inland waterways of the Federal
Section 14, D. Republic of Germany with the exception of the river

new A.2.7 Rhine and river Danube the "Binnenschiffs-Unter-
suchungsordnung" is to be observed. For navigation
For the substructures of windlasses and chain stop- on the river Rhine, the "Rheinschiffs-Untersuchungs-
pers, see Section 10, B.5. ordnung" and for navigation on the river Danube, the

new A.2.2 "Verordnung über die Untersuchung der Donau-
schiffe" are to be observed.
Chapter 1 Section 18 C Equipment I - Part 1
Page 18–2 GL 2012

new A.2.8 2. The equipment numeral Z2 for the recom-

mended selection of ropes as well as for the determi-
nation of the design load for shipboard towing and
mooring equipment and supporting hull structure is to
B. Equipment numeral
be calculated as follows:

1. The equipment numeral Z1 for anchors and A

Z2 = D2 / 3 + 2 h B +
chain cables is to be calculated as follows: 10
A D = moulded displacement [t] in sea water having
Z1 = D2 / 3 + 2 h B + a density of 1,025 t/m3 to the summer load
10
waterline
D = moulded displacement [t] in sea water having
a density of 1,025 t/m3 to the summer load h = effective height from the summer load water-
waterline line to the top of the uppermost house
h = effective height from the summer load water- = a + Σhi
line to the top of the uppermost house
a = distance [m], from the summer load water-
= a + Σhi line, amidships, to the upper deck at side
a = distance [m], from the summer load water- Σhi = sum of height [m] of superstructures and deck-
line, amidships, to the upper deck at side houses on the upper deck, measured on the
Σhi = sum of height [m] of superstructures and centreline of each tier. Deck sheer, if any, is to
deckhouses on the upper deck, measured on be ignored. For the lowest tier, "h" is to be
the centreline of each tier having a breadth measured at centreline from the upper deck or
greater than B/4. Deck sheer, if any, is to be from a notional deck line where there is local
ignored. For the lowest tier, "h" is to be discontinuity in the upper deck.
measured at centreline from the upper deck A = area [m2], in profile view of the hull, super-
or from a notional deck line where there is structures and deckhouses above the summer
local discontinuity in the upper deck. load waterline within the length L.
A = area [m2], in profile view of the hull, super- Screens of bulwarks, hatch coamings and
structures and deckhouses, having a breadth deck equipment, e.g., masts and lifting gear,
greater than B/4, above the summer load wa- as well as containers on deck have to be ob-
terline within the length L and up to the served for the calculation of A.
height h

new B.2
Where a deckhouse having a breadth greater than B/4
is located above a deckhouse having a breadth of B/4
or less, the wider house is to be included and the nar-
row house ignored. C. Anchors

Screens of bulwarks 1,5 m or more in height are to be 1. The number of bower anchors is to be deter-
regarded as parts of houses when determining h and mined according to column 3 of Table 18.2. Two of
A, e.g. the area shown in Fig. 18.1 as A1 is to be in- the rule bower anchors are to be connected to their
cluded in A. The height of the hatch coamings and that chain cables and positioned on board ready for use.
of any deck cargo, such as containers, may be disre-
garded when determining h and A.
new C.1.1

new B.1 It is to be ensured that each anchor can be stowed in

the hawse and hawse pipe in such a way that it re-
mains firmly secured in seagoing conditions. Details
have to be coordinated with the owner.
A1
new C.1.2
1.5m

Where in column 3 of Table 18.2 two bow anchors are

required, a stream anchor shall be on board as a third
LWL anchor. Its mass shall be according to column 5 of the
table. Length and breaking load of chain or stream wire
respectively are to be as given in columns 10 and 11.
F. P.

new C.1.1
Fig. 18.1 Effective area A1 of bulwark Where in column 3 of Table 18.2 three bower anchors
are required, the third anchor is intended as a spare
I - Part 1 Section 18 C Equipment Chapter 1
GL 2012 Page 18–3

bower anchor. Installation of the spare bower anchor are to be carried out on at least two sizes of anchors in
on board is not required. association with the chain cables appropriate to the
weight. The anchors to be tested and the standard

new C.1.1
stockless anchors should be of approx. the same mass.
The spare anchor is not required as a condition of The chain length used in the tests should be approx. 6
classification and, with owner's consent, may be dis- to 10 times the depth of water.
pensed with.
The tests are normally to be carried out from a tug,

new C.1.1 however, alternative shore based tests (e.g. with suit-
able winches) may be accepted.
Note
Three tests are to be carried out for each anchor and
National regulations concerning the provision of a type of bottom. The pull shall be measured by means
spare anchor, stream anchor or a stern anchor may of a dynamometer or recorded by a recording instru-
need to be observed. ment. Measurements of pull based on rpm/bollard pull

new C.1.3 curve of the tug may be accepted.

A stern anchor in the sense of these Rules is named a Testing by comparison with a previously approved
HHP anchor may be accepted as a basis for approval.
stream anchor of small seagoing ships, i.e. up to and
The maximum mass of an anchor thus approved may be
including the equipment numeral of Z1 = 205.
10 times the mass of the largest size of anchor tested.

new A.3 The dimensioning of the chain cable and of the wind-
lass is to be based on the undiminished anchor mass
2. Anchors shall be of approved design. The according to the Tables.
mass of the heads of patent (ordinary stockless) an-
new C.4.3
chors, including pins and fittings, is not to be less than
60 per cent of the total mass of the anchor.
6. Where stern anchor equipment is fitted, such

new C.3.1 and C.3.2 equipment is to comply in all respects with the rules for
anchor equipment. The mass of each stern anchor shall
3. For stock anchors, the total mass of the an- be at least 35 per cent of that of the bower anchors.
chor, including the stock, shall comply with the values The diameter of the chain cables and the chain length
in Table 18.2. The mass of the stock shall be 20 per are to be determined from the Tables in accordance
cent of this total mass. with the anchor mass. Where a stern anchor windlass is
fitted the requirements of the GL Rules for Machinery

new C.2 Installations (I-1-2), Section 14, are to be observed.

4. The mass of each individual bower anchor may
new C.5.1

vary by up to 7 per cent above or below the required
individual mass provided that the total mass of all the 7. Where a steel wire rope is to be used for the
bower anchors is not less than the sum of the required stern anchor instead of a chain cable the following has
individual masses. to be observed:

new C.3.3
new C.5.2

7.1 The steel wire rope shall at least be as long as

5. Where special anchors approved as "High
the required chain cable. The strength of the steel wire
Holding Power Anchors" are used, the anchor mass
rope shall at least be of the value for the required
may be 75 per cent of the anchor mass as per Table
chain of grade K1.
18.2.

new C.5.2.1

new C.4.2
"High Holding Power Anchors" are anchors which are 7.2 Between anchor and steel wire rope a shot of
suitable for ship's use at any time and which do not 12,5 m in length or of the distance between stowed
require prior adjustment or special placement on the anchor and windlass shall be provided. The smaller
sea bed. length has to be taken.

new C.4.1
new C.5.2.2
For approval as a "High Holding Power Anchor",
satisfactory tests are to be made on various types of 7.3 A cable winch shall be provided according to
bottom and the anchor is to have a holding power at the requirements for windlasses in the GL Rules for
least twice that of a patent anchor ("Admiralty Stan- Machinery Installation (I-1-2), Section 14, B.
dard Stockless") of the same mass. The mass of an-
new C.5.2.3
chors to be tested should be representative of the full
range of sizes intended to be manufactured. The tests
Chapter 1 Section 18 E Equipment I - Part 1
Page 18–4 GL 2012

D. Chain Cables E. Chain Locker

1. The chain cable diameters given in the Tables 1. The chain locker is to be of capacity and
apply to chain cables made of chain cable materials depth adequate to provide an easy direct lead of the
specified in the GL Rules for Metallic Materials (II-1), cables through the chain pipes and self-stowing of the
for the following grades: cables.
– Grade K1 (ordinary quality) The minimum required stowage capacity without mud
box for the two bow anchor chains is as follows:
– Grade K2 (special quality)
ℓ
– Grade K3 (extra special quality) S = 1,1 ⋅ d 2 ⋅ [m3 ]
100 000

new D.1
d = chain diameter [mm] according to Table 18.2
2. Grade K1 material used for chain cables in ℓ = total length of stud link chain cable according
conjunction with "High Holding Power Anchors" shall to Table 18.2
have a tensile strength Rm of not less than 400 N/mm2.
The total stowage capacity is to be distributed on two

new D.2 chain lockers of equal size for the port and starboard
chain cables. The shape of the base areas shall as far
3. Grade K2 and K3 chain cables shall be post as possible be quadratic with a maximum edge length
production quenched and tempered and purchased of 33 d. As an alternative, circular base areas may be
from recognized manufacturers only. selected, the diameter of which shall not exceed 30 –
35 d.

new D.3
Above the stowage of each chain locker in addition a
4. The total length of chain given in Table 18.2 free depth of
is to be divided in approximately equal parts between
h = 1 500 [mm]
the two bower anchors.

new D.4 is to be provided.

new E.1
5. Either stud link or short link chain cables
may be used for stream anchors. 2. The chain locker boundaries and their access

new D.5 openings are to be watertight to prevent flooding of
adjacent spaces, where essential installations or
equipment are arranged, in order to not affect the
6. For connection of the anchor with the chain
proper operation of the ship after accidental flooding
cable approved Kenter-type anchor shackles may be
of the chain locker.
chosen in lieu of the common Dee-shackles. A fore-
runner with swivel is to be fitted between anchor and
new E.2
chain cable. In lieu of a forerunner with swivel an
approved swivel shackle may be used. However, 2.1 Special requirements to minimize the in-
swivel shackles are not to be connected to the anchor gress of water
shank unless specially approved. A sufficient number
of suitable spare shackles are to be kept on board to 2.1.1 Spurling pipes and cable lockers are to be
facilitate fitting of the spare anchor at any time. On watertight up to the weather deck.
owner's request the swivel shackle may be dispensed
with.
new E.2.1.1

new D.6 2.1.2 Where means of access is provided, it is to be

closed by a substantial cover and secured by closely
7. The attachment of the inboard ends of the spaced bolts.
chain cables to the ship's structure is to be provided
new E.2.1.2
with means suitable to permit, in case of emergency,
an easy slipping of the chain cables to sea operable 2.1.3 Spurling pipes through which anchor cables
from an accessible position outside the chain locker. are led are to be provided with permanently attached
The inboard ends of the chain cables are to be secured closing appliances to minimize water ingress.
to the structures by a fastening able to withstand a
new E.2.1.3
force not less than 15 % nor more than 30 % of the
rated breaking load of the chain cable. 3. Adequate drainage facilities of the chain

new D.7 locker are to be provided.
I - Part 1 Section 18 F Equipment Chapter 1
GL 2012 Page 18–5

new E.3 Synthetic

wire ropes Fibre ropes
Steel wire
4. Where the chain locker boundaries are also ropes 1 polypro-
polyamide 2 polyamide polyester pylene
tank boundaries their scantlings of stiffeners and plat-
ing are to be determined as for tanks in accordance diam. diam. diam. diam. diam.
with Section 12. [mm] [mm] [mm] [mm] [mm]
Where this is not the case the plate thickness is to be 12 30 30 30 30
determined as for t2 and the section modulus as for W2 13 30 32 32 32
in accordance with Section 12, B.2. and B.3. respec- 14 32 36 36 36
tively. The distance from the load centre to the top of
16 32 40 40 40
the chain locker pipe is to be taken for calculating the
18 36 44 44 44
load.
20 40 48 48 48

new E.4
22 44 48 48 52
24 48 52 52 56
5. For the location of chain lockers on tankers
Section 24, A.9 is to be observed. 26 56 60 60 64
28 60 64 64 72

new E.5
32 68 72 72 80
36 72 80 80 88
40 72 88 88 96
F. Mooring Equipment 1 1 according to DIN 3068 or similar.
2 Regular laid ropes of refined polyamide monofilaments and
1. Ropes filament fibres.

1.1 The following items 1.2 to 1.6 and the Tables 1.3 Where the stream anchor is used in conjunc-
18.1 and 18.2 for tow lines and mooring ropes are tion with a rope, this is to be a steel wire rope.
recommendations only, a compliance with which is
not a condition of Class.
new F.3.3

new F.3.1 1.4 Wire ropes shall be of the following type:
1.2 For tow lines and mooring lines, steel wire – 6 × 24 wires with 7 fibre cores for breaking
ropes as well as fibre ropes made of natural or syn- loads of up to 500 kN
thetic fibres or wire ropes consisting of steel wire and
fibre cores may be used. The breaking loads specified type: Standard
in Table 18.2 are valid for wire ropes and ropes of – 6 × 36 wires with 1 fibre core for breaking loads
natural fibre (manila) only. Where ropes of synthetic of more than 500 kN
fibre are used, the breaking load is to be increased
above the table values. The extent of increase depends type: Standard
on the material quality. Where wire ropes are stored on mooring winch drums,
The required diameters of synthetic fibre ropes used in steel cored wire ropes may be used e.g.:
lieu of steel wire ropes may be taken from Table 18.1.
– 6 × 19 wires with 1 steel core

new F.3.2 type: Seale

Table 18.1 Wire/fibre ropes diameter – 6 × 36 wires with 1 steel core

type: Warrington-Seale

1.5 Regardless of the breaking load, recom-

mended in Table 18.2, the diameter of fibre ropes
should not be less than 20 mm.

1.6 The length of the individual mooring ropes

may be up to 7 per cent less than that given in the
table provided that the total length of all the wires and
ropes is not less than the sum of the required individ-
ual lengths.
Where mooring winches on large ships are located on
1 one side of the ship, the lengths of mooring ropes
For approximating the mooring forces a GL-computer program
system is available. should be increased accordingly.
Chapter 1 Section 18 F Equipment I - Part 1
Page 18–6 GL 2012

For individual mooring lines with a breaking load above
new F.1.5.3
500 kN the following alternatives may be applied:
(4) The towing and mooring arrangement plan men-
– The breaking load of the individual mooring lines tioned in H. is to define the method of use of
specified in Table 18.2 may be reduced with cor- mooring lines.
responding increase of the number of mooring
lines, provided that the total breaking load of all
new F.1.5.4
lines aboard ship is not less than the rule value as
per Table 18.2. No mooring line, however, 3. Supporting hull structure for mooring
should have a breaking load of less than 500 kN. equipment
– The number of mooring lines may be reduced with Strength calculations for supporting hull structures of
corresponding increase of the breaking load of the mooring equipment are to be based on net thick-
individual mooring lines, provided that the total nesses.
breaking load of all lines aboard ship is not less
than the rule value specified in Table 18.2, how- tnet = t – tk
ever, the number of lines should not be less than 6.
tk = corrosion addition according to 4.

new F.3.4

new F.1.4.1
2. Shipboard fittings (mooring bollards and
bitts, fairleads, stand rollers, chocks) 3.1 Load considerations
The selection of shipboard fittings is to be made by (1) Unless greater safe working load (SWLGL) of
the shipyard in accordance with an industry standard
shipboard fittings is specified by the applicant,
(e.g. ISO 3913 Shipbuilding Welded Steel Bollards)
the design load applied to shipboard fittings and
accepted by GL. In such cases the safety factors of the
supporting hull structures is to be 1,25 times
standard are to be complied with. When the shipboard
the breaking strength of the mooring line accord-
fitting is not selected from an accepted industry stan-
ing to Table 18.2 for the equipment numeral
dard, the strength of the fitting and its attachment to
Z2.
the ship is to be assessed in accordance with 3.

new F.1.3.2 When ropes with increased breaking strength are
used, the design load needs not to be in excess
2.1 Arrangement of 1,25 times the breaking strength of the moor-
ing line according to Table 18.2 for the equip-
Shipboard fittings for mooring are to be located on ment numeral Z2. This is not applicable, if the
longitudinals, beams and/or girders, which are part of breaking strength of the ropes is increased in ac-
the deck construction so as to facilitate efficient distri- cordance with 1.6.
bution of the mooring load. Other arrangements may
be accepted (for Panama chocks, etc.) provided the
new F.1.2.1
strength is confirmed adequate for the service.
(2) The minimum design load applied to supporting

new F.1.3.1 hull structures for winches, etc. is to be the de-
sign load acc. to (1). For capstans, the minimum
2.2 Safe working load (SWLGL) design load is to be 1,25 times the maximum
hauling-in force.
(1) The safe working load for fittings is to be calcu-
new F.1.2.2
lated as follows:
(3) The design load is to be applied through the moor-
FD ing line according to the arrangement shown on
SWLGL =
1,875 the towing and mooring arrangement plan, see
Fig. 18.2.
FD = design load per 3.1.

new F.1.2.3

new F.1.5.1

(2) The SWLGL of each shipboard fitting is to be

marked (by weld bead or equivalent) on the
deck fittings used for mooring.

new F.1.5.2

(3) The above requirements on SWLGL apply for a

single post basis (no more than one turn of one
cable).
I - Part 1 Section 18 G Equipment Chapter 1
GL 2012 Page 18–7

5. Equipment for mooring at single point

on li ign load
moorings (SPM)

ne
5.1 Upon request from the owner, GL is prepared

Des
ing
n fitt s e
to certify that the vessel is specially fitted for compli-
d o tim ) ance with the applicable sections of "Recommenda-
l oa than 2n line tions for Equipment Employed in the Bow Mooring of
n o
sig ore ad Conventional Tankers at Single Point Moorings" pub-
De Not mign lo
( es lished by the Oil Companies International Marine
D
Forum (OCIMF), 2007.

new F.2.1
Design load on
Fitting line
5.2 For tankers employed in shuttle service using
single point moorings (SPM) Section 24, K. has to be
Fig. 18.2 Application of design loads observed.

new F.2.2
(4) When a specific SWLGL, that is greater than
required in 2.2 (1), is applied for a fitting at the
request of the applicant, the fitting and the sup- G. Towing Equipment
porting hull structure have to be designed using
the requested SWLGL times 1,875 as design 1. Shipboard fittings and supporting hull
load. structures

new F.1.2.5 1.1 Arrangement and strength
(5) The acting point of the mooring force on ship- Shipboard fittings for towing are to be located on
board fittings is to be taken at the attachment longitudinals, beams and/or girders, which are part of
point of a mooring line or at a change in its di- the deck construction so as to facilitate efficient distri-
rection. bution of the towing load. Other arrangements may be
accepted provided the strength is confirmed adequate
For bollards, the acting point of the design load for the intended service.
is to be taken at least equivalent to the diameter
of the pipe above deck level. Special designs
new G.1.3.1
have to be evaluated individually.
The strength of shipboard fittings used for ordinary

new F.1.4.3 towing operations (not emergency towing) at bow,
sides and stern and their supporting hull structures are
3.2 Allowable stresses to be determined on the basis of 1.1.1 and 1.1.2.

new G.1.1.1
Normal stress: σN ≤ ReH
Strength calculations are to be based on net thick-
Shear stress: τ ≤ 0,6 ReH nesses
Equivalent stress: σV ≤ ReH tnet = t – tk

new F.1.4.4 tk = corrosion addition, see F.4.

new G.1.4.1
4. Corrosion addition
1.1.1 Load considerations
The total corrosion addition tk for both sides of the hull
supporting structure is not to be less than the follow- Unless greater safe working load (SWLGL) of ship-
ing values: board fittings is specified by the applicant, the mini-
mum design load to be used is the following value of
– Ships covered by CSR for bulk carriers and CSR (1) or (2), whichever is applicable:
for double hull oil tankers: Total corrosion addi-
tions defined in these rules
new G.1.2.1
– Other ships: 2,0 mm in general and 1,0 mm in (1) for normal towing operations (e.g., in harbour)
dry spaces using fittings at bow, sides and stern, 1,875
times the intended maximum towing load (e.g.

new F.1.4.5 static bollard pull) as indicated on the towing
and mooring arrangement plan.
Chapter 1 Section 18 H Equipment I - Part 1
Page 18–8 GL 2012

If the intended maximum towing load is not FD

specified by the applicant, the nominal breaking SWLGL =
1,5
strength of the corresponding mooring lines ac-
cording to Table 18.2 for the equipment numeral FD = design load per 1.1.1(2).
Z2 is to be applied.

new G.1.5.1

new G.1.2.1
(3) For chocks and bollards of which the strength shall
(2) for other towing service using the forward main comply with Panama Canal Regulations, the safe
towing fittings, in general arranged on forecastle working load is not to exceed the following value:
deck at the vessel's centre line, the nominal break-
ing strength of the tow line according to Table FD
SWLGL =
18.2 for the equipment numeral Z2. 1,875

new G.1.2.1 FD = design load according to Panama Canal
(3) The design load is to be applied through the tow Regulations.
line according to the arrangement shown on the
towing and mooring arrangement plan, see Fig.
new G.1.5.1
18.2.
(4) The SWLGL of each shipboard fitting is to be

new G.1.2.2 marked (by weld bead or equivalent) on the
For bollards, the acting point of the design load deck fittings used for towing.
is to be taken at least equivalent to the diameter
of the pipe above deck level. Special designs For fittings, which are used for different moor-
have to be evaluated individually. ing or towing operations, the greater of the safe
working loads SWLGL is to be marked.

new G.1.4.3

new G.1.5.2
(4) When a specific SWLGL, that is greater than re-
quired in 1.2, is applied for a fitting at the request (5) The above requirements on SWLGL apply for a
of the applicant, the fitting and the supporting single post basis (no more than one turn of one
hull structure have to be designed using the fol- cable).
lowing design loads:
new G.1.5.3
– requested SWLGL times 1,875 for normal
towing operations (6) The towing and mooring arrangement plan men-
tioned in H. is to define the method of use of
– requested SWLGL times 1,5 for other tow- towing lines.
ing service

new G.1.5.4

new G.1.2.3

1.1.2 Allowable stresses 2. Shipboard fittings and supporting hull

structures for escort towing
Normal stress: σN ≤ ReH For shipboard fittings intended to be used for escort
Shear stress: τ ≤ 0,6 ReH towing as required e.g. for laden tankers in some areas
in the United States, the provisions in 1. as given for
Equivalent stress: σV ≤ ReH other towing services are to be applied analogously.

new G.1.4.4
new G.2

1.2 Safe working load (SWLGL)

(1) The safe working load for a shipboard fitting H. Towing and Mooring Arrangement Plan
used for normal towing operations is not to ex-
ceed the following value: The SWLGL for the intended use for each shipboard
fitting is to be noted in the towing and mooring ar-
FD
SWLGL = rangement plan available on board for the guidance of
1,875 the Master.
FD = design load per 1.1.1(1) Information provided on the plan is to include in re-

new G.1.5.1 spect of each shipboard fitting:

(2) The safe working load for a shipboard fitting used – location on the ship
for other towing service (i.e., for the main tow- – fitting type
ing fittings) is not to exceed the following value:
I - Part 1 Section 18 H Equipment Chapter 1
GL 2012 Page 18–9

– SWLGL This information is to be incorporated into the pilot

card in order to provide the pilot proper information
– purpose (mooring, normal towing operations / on harbour/escorting operations.
other towing services); and

new H
– manner of applying towing or mooring line load
including limiting fleet angles.
Chapter 1 Section 18 H Equipment I - Part 1
Page 18–10 GL 2012

Table 18.2 Anchor, Chain Cables and Ropes

Stockless anchor Stud link chain cables Recommended ropes

Stream wire
or chain
Equipment Bower anchor Stream Bower anchors Towline Mooring ropes
No. anchor for stream
for numeral anchor
Reg.
Z1 or Z2 Diameter
Mass per Total Br. Br. Br.
Num- Length Length Length
anchor length Load 2 Load 2 Num- Load 2
ber 1 d1 d2 d3 ber
[kg] [m] [mm] [mm] [mm] [m] [kN] [m] [kN] [m] [kN]
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

101 up to 50 2 120 40 165 12,5 12,5 12,5 80 65 180 100 3 80 35

102 50 – 70 2 180 60 220 14 12,5 12,5 80 65 180 100 3 80 35
103 70 – 90 2 240 80 220 16 14 14 85 75 180 100 3 100 40
104 90 – 110 2 300 100 247,5 17,5 16 16 85 80 180 100 3 110 40
105 110 – 130 2 360 120 247,5 19 17,5 17,5 90 90 180 100 3 110 45
106 130 – 150 2 420 140 275 20,5 17,5 17,5 90 100 180 100 3 120 50
107 150 – 175 2 480 165 275 22 19 19 90 110 180 100 3 120 55
108 175 – 205 2 570 190 302,5 24 20,5 20,5 90 120 180 110 3 120 60
109 205 – 240 3 660 302,5 26 22 20,5 180 130 4 120 65
110 240 – 280 3 780 330 28 24 22 180 150 4 120 70
111 280 – 320 3 900 357,5 30 26 24 180 175 4 140 80
112 320 – 360 3 1020 357,5 32 28 24 180 200 4 140 85
113 360 – 400 3 1140 385 34 30 26 180 225 4 140 95
114 400 – 450 3 1290 385 36 32 28 180 250 4 140 100
115 450 – 500 3 1440 412,5 38 34 30 180 275 4 140 110
116 500 – 550 3 1590 412,5 40 34 30 190 305 4 160 120
117 550 – 600 3 1740 440 42 36 32 190 340 4 160 130
118 600 – 660 3 1920 440 44 38 34 190 370 4 160 145
119 660 – 720 3 2100 440 46 40 36 190 405 4 160 160
120 720 – 780 3 2280 467,5 48 42 36 190 440 4 170 170
121 780 – 840 3 2460 467,5 50 44 38 190 480 4 170 185
122 840 – 910 3 2640 467,5 52 46 40 190 520 4 170 200
123 910 – 980 3 2850 495 54 48 42 190 560 4 170 215
124 980 – 1060 3 3060 495 56 50 44 200 600 4 180 230
125 1060 – 1140 3 3300 495 58 50 46 200 645 4 180 250
126 1140 – 1220 3 3540 522,5 60 52 46 200 690 4 180 270
127 1220 – 1300 3 3780 522,5 62 54 48 200 740 4 180 285
128 1300 – 1390 3 4050 522,5 64 56 50 200 785 4 180 305
129 1390 – 1480 3 4320 550 66 58 50 200 835 4 180 325
130 1480 – 1570 3 4590 550 68 60 52 220 890 5 190 325
131 1570 – 1670 3 4890 550 70 62 54 220 940 5 190 335
132 1670 – 1790 3 5250 577,5 73 64 56 220 1025 5 190 350
133 1790 – 1930 3 5610 577,5 76 66 58 220 1110 5 190 375
134 1930 – 2080 3 6000 577,5 78 68 60 220 1170 5 190 400
135 2080 – 2230 3 6450 605 81 70 62 240 1260 5 200 425
136 2230 – 2380 3 6900 605 84 73 64 240 1355 5 200 450
137 2380 – 2530 3 7350 605 87 76 66 240 1455 5 200 480
138 2530 – 2700 3 7800 632,5 90 78 68 260 1470 6 200 480
139 2700 – 2870 3 8300 632,5 92 81 70 260 1470 6 200 490
140 2870 – 3040 3 8700 632,5 95 84 73 260 1470 6 200 500
141 3040 – 3210 3 9300 660 97 84 76 280 1470 6 200 520
142 3210 – 3400 3 9900 660 100 87 78 280 1470 6 200 555
143 3400 – 3600 3 10500 660 102 90 78 280 1470 6 200 590
144 3600 – 3800 3 11100 687,5 105 92 81 300 1470 6 200 620
145 3800 – 4000 3 11700 687,5 107 95 84 300 1470 6 200 650
146 4000 – 4200 3 12300 687,5 111 97 87 300 1470 7 200 650
147 4200 – 4400 3 12900 715 114 100 87 300 1470 7 200 660
148 4400 – 4600 3 13500 715 117 102 90 300 1470 7 200 670
149 4600 – 4800 3 14100 715 120 105 92 300 1470 7 200 680
150 4800 – 5000 3 14700 742,5 122 107 95 300 1470 7 200 685
151 5000 – 5200 3 15400 742,5 124 111 97 300 1470 8 200 685
152 5200 – 5500 3 16100 742,5 127 111 97 300 1470 8 200 695
153 5500 – 5800 3 16900 742,5 130 114 100 300 1470 8 200 705
154 5800 – 6100 3 17800 742,5 132 117 102 300 1470 9 200 705
155 6100 – 6500 3 18800 742,5 120 107 300 1470 9 200 715
156 6500 – 6900 3 20000 770 124 111 300 1470 9 200 725
157 6900 – 7400 3 21500 770 127 114 300 1470 10 200 725
158 7400 – 7900 3 23000 770 132 117 300 1470 11 200 725
159 7900 – 8400 3 24500 770 137 122 300 1470 11 200 735
160 8400 – 8900 3 26000 770 142 127 300 1470 12 200 735
161 8900 – 9400 3 27500 770 147 132 300 1470 13 200 735
162 9400 – 10000 3 29000 770 152 132 300 1470 14 200 735
163 10000 – 10700 3 31000 770 137 300 1470 15 200 735
164 10700 – 11500 3 33000 770 142 300 1470 16 200 735
165 11500 – 12400 3 35500 770 147 300 1470 17 200 735
166 12400 – 13400 3 38500 770 152 300 1470 18 200 735
167 13400 – 14600 3 42000 770 157 300 1470 19 200 735
168 14600 – 16000 3 46000 770 162 300 1470 21 200 735

d1 = Chain diameter Grade K 1 (Ordinary quality) 

d 2 = Chain diameter Grade K 2 (Special quality)  See also D.
d 3 = Chain diameter Grade K 3 (Extra special quality) 
1 see C.1.
2 see F.1.2
I - Part 1 Section 19 A Welded Joints Chapter 1
GL 2012 Page 19–1

Section 19

Welded Joints

2.3 Higher strength hull structural steels grade

in this Section are no changes in numbering
AH/DH/EH/FH which have been approved by GL in
Preface accordance with the relevant requirements of Rules for
Materials and Welding normally have had their weld-
The content of this Section is to a large extent identi-
ability examined and, provided their handling is in
cal to that of the GL Rules for Welding in the Various
accordance with normal shipbuilding practice, may be
Fields of Application (II-3-3), Section 1, G. Because
considered to be proven. The suitability of these base
of the re-issues of Chapter 3 referred to and this
materials for high efficiency welding processes with
Chapter 1 at different times, some temporary diver-
high heat input shall be verified.
gences may arise and in such circumstances the more
recent Rules shall take precedence.
2.4 High strength (quenched and tempered) fine
grain structural steels, low temperature steels, stainless
and other (alloyed) structural steels require special
A. General approval by GL. Proof of weldability of the respective
steel is to be presented in connection with the welding
procedure and welding consumables.
1. Information contained in manufacturing
documents
2.5 Cast steel and forged parts require testing by
GL. For castings intended to be used for welded ship-
1.1 The shapes and dimensions of welds and, building structures the maximum permissible values
where proof by calculation is supplied, the require- of the chemical composition according to the GL
ments applicable to welded joints (the weld quality Rules for Steel and Iron Materials (II-1-2), Section 4,
grade, detail category) are to be stated in drawings and B.4. and Table 4.1 have to be observed.
other manufacturing documents (parts lists, welding
and inspection schedules). In special cases, e.g. where
special materials are concerned, the documents shall 2.6 Aluminium alloys require testing by GL.
also state the welding method, the welding consum- Proof of their weldability shall be presented in con-
ables used, heat input and control, the weld build-up nection with the welding procedure and welding con-
and any post-weld treatment which may be required. sumables.

1.2 Symbols and signs used to identify welded 2.7 Welding consumables used are to be suitable
joints shall be explained if they depart from the sym- for the parent metal to be welded and are to be ap-
bols and definitions contained in the relevant stan- proved by GL.
dards (e.g. DIN standards). Where the weld prepara-
tion (together with approved methods of welding)
3. Manufacture and testing
conforms both to normal shipbuilding practice and to
these Rules and recognized standards, where applica-
ble, no special description is needed. 3.1 The manufacture of welded structural com-
ponents may only be carried out in workshops or
plants that have been approved. The requirements that
2. Materials, weldability have to be observed in connection with the fabrication
of welded joints are laid down in the GL Rules for
2.1 Only base materials of proven weldability Welding (II-3).
(see Section 2) may be used for welded structures.
Any approval conditions of the steel or of the proce- 3.2 The weld quality grade of welded joints with-
dure qualification tests and the steelmaker's recom- out proof by calculation (see 1.1) depends on the sig-
mendations are to be observed. nificance of the welded joint for the total structure and
on its location in the structural element (location to the
2.2 For normal strength hull structural steels main stress direction) and on its stressing. For details
grades A, B, D and E which have been tested by GL, concerning the type, scope and manner of testing, see
weldability normally is considered to have been the GL Rules for Welding in the Various Fields of
proven. The suitability of these base materials for Application (II-3-3), Section 1, I. Where proof of
high efficiency welding processes with high heat input fatigue strength is required, in addition the require-
shall be verified. ments of Section 20 apply.
Chapter 1 Section 19 B Welded Joints I - Part 1
Page 19–2 GL 2012

B. Design 2. Design details

1. General design principles 2.1 Stress flow, transitions

2.1.1 All welded joints on primary supporting

1.1 During the design stage welded joints are to members shall be designed to provide as smooth a
be planned such as to be accessible during fabrication, stress profile as possible with no major internal or
to be located in the best possible position for welding external notches, no discontinuities in rigidity and no
and to permit the proper welding sequence to be fol- obstructions to strains, see Section 3, H.
lowed.

2.1.2 This applies in analogous manner to the

1.2 Both the welded joints and the sequence of welding of subordinate components on to primary
welding involved are to be so planned as to enable supporting members whose exposed plate or flange
residual welding stresses to be kept to a minimum in edges should, as far as possible, be kept free from
order that no excessive deformation occurs. Welded notch effects due to welded attachments. Regarding
joints should not be over dimensioned, see also 3.3.3. the inadmissibility of weldments to the upper edge of
the sheer strake, see Section 6, C.3.4. This applies
similarly to weldments to the upper edge of continu-
1.3 When planning welded joints, it shall first be ous hatchway side coamings.
established that the type and grade of weld envisaged,
such as full root weld penetration in the case of HV or
DHV (K) weld seams, can in fact be perfectly exe- 2.1.3 Butt joints in long or extensive continuous
cuted under the conditions set by the limitations of the structures such as bilge keels, fenders, crane rails, slop
manufacturing process involved. If this is not the case, coamings, etc. attached to primary structural members
a simpler type of weld seam shall be selected and its are therefore to be welded over their entire cross-
possibly lower load bearing capacity taken into ac- section.
count when dimensioning the component.
2.1.4 Wherever possible, joints (especially site
joints) in girders and sections shall not be located in
1.4 Highly stressed welded joints - which, there- areas of high bending stress. Joints at the knuckle of
fore, are generally subject to examination - are to be flanges are to be avoided.
so designed that the most suitable method of testing
for faults can be used (radiography, ultrasonic, surface
crack testing methods) in order that a reliable exami- 2.1.5 The transition between differing component
nation may be carried out. dimensions shall be smooth and gradual. Where the
depth of web of girders or sections differs, the flanges
or bulbs are to be bevelled and the web slit and ex-
1.5 Special characteristics peculiar to the mate- panded or pressed together to equalize the depths of
rial, such as the lower strength values of rolled mate- the members. The length of the transition should be at
rial in the thickness direction (see 2.5.1) or the soften- least equal twice the difference in depth.
ing of cold worked aluminium alloys as a result of
welding, are factors which have to be taken into ac- 2.1.6 Where the plate thickness differs at joints
count when designing welded joints. Clad plates perpendicularly to the direction of the main stress,
where the efficiency of the bond between the base and differences in thickness greater than 3 mm shall be
the clad material is proved may generally be treated as accommodated by bevelling the proud edge in the
solid plates (up to medium plate thicknesses where manner shown in Fig. 19.1 at a ratio of at least 1 : 3 or
mainly filled weld connections are used). according to the notch category. Differences in thick-
ness of 3 mm or less may be accommodated within the
weld.
1.6 In cases where different types of material are
paired and operate in sea water or any other electro-
max. 3

lytic medium, for example welded joints made be-

tween unalloyed carbon steels and stainless steels in 3
the wear-resistant cladding in rudder nozzles or in the £ 1:
cladding of rudder shafts, the resulting differences in
potential greatly increase the susceptibility to corro-
sion and shall therefore be given special attention.
Where possible, such welds are to be positioned in
locations less subject to the risk of corrosion (such as
on the outside of tanks) or special protective counter-
measures are to be taken (such as the provision of a Fig. 19.1 Accommodation of differences of thick-
protective coating or cathodic protection). ness
I - Part 1 Section 19 B Welded Joints Chapter 1
GL 2012 Page 19–3

2.1.7 For the welding on of plates or other rela- 2.3 Welding cut-outs
tively thin-walled elements, steel castings and forgings
should be appropriately tapered or provided with inte- 2.3.1 Welding cut-outs for the (later) execution of
grally cast or forged welding flanges in accordance butt or fillet welds following the positioning of trans-
with Fig. 19.2. verse members should be rounded (minimum radius
25 mm or twice the plate thickness, whichever is the
greater) and should be shaped to provide a smooth
transition on the adjoining surface as shown in Fig.
19.3 (especially necessary where the loading is mainly
dynamic).

r ³ 2t ³ 25
[t]
Fig. 19.2 Welding flanges on steel castings or
forgings

2.1.8 For the connection of shaft brackets to the

boss and shell plating, see 4.3 and Section 13, D.2.;
for the connection of horizontal coupling flanges to r ³ 2t ³ 25
the rudder body, see 4.4. For the required thickened
rudderstock collar required with build-up welds and [t]
for the connection of the coupling flange, see 2.7 and
Section 14, D.2.4. Rudderstock and coupling flange
are to be connected by full penetration weld.
Fig. 19.3 Welding cut-outs
2.2 Local clustering of welds, minimum
2.3.2 Where the welds are completed prior to the
spacing positioning of the crossing members, no welding cut-
outs are needed. Any weld reinforcements present are
2.2.1 The local clustering of welds and short dis- to be machined off prior to the location of the crossing
tances between welds are to be avoided. Adjacent butt members or these members are to have suitable cut-
welds should be separated from each other by a dis- outs.
tance of at least

50 mm + 4 × plate thickness 2.4 Local reinforcements, doubling plates

Fillet welds should be separated from each other and
2.4.1 Where platings (including girder plates and
from butt welds by a distance of at least
tube walls) are subjected locally to increased stresses,
30 mm + 2 × plate thickness thicker plates should be used wherever possible in
preference to doubling plates. Bearing bushes, hubs
The width of replaced or inserted plates (strips) etc. shall invariably take the form of thicker sections
should, however, be at least 300 mm or ten times the welded into the plating, see 2.2.2.
plate thickness, whichever is the greater.
2.4.2 Where doublings cannot be avoided, the
2.2.2 Reinforcing plates, welding flanges, mount- thickness of the doubling plates should not exceed
ings and similar components socket-welded into plat- twice the plating thickness. Doubling plates whose
ing should be of the following minimum size: width is greater than approximately 30 times their
thickness shall be plug welded to the underlying plat-
D min = 170 + 3 (t − 10) ≥ 170 mm ing in accordance with 3.3.11 at intervals not exceed-
ing 30 times the thickness of the doubling plate.
D = diameter of round or length of side of angular
weldments [mm] 2.4.3 Along their (longitudinal) edges, doubling
plates shall be continuously fillet welded with a throat
t = plating thickness [mm]
thickness "a" of 0,3 × the doubling plate thickness. At
The corner radii of angular socket weldments should the ends of doubling plates, the throat thickness "a" at
be 5 t [mm] but at least 50 mm. Alternatively the the end faces shall be increased to 0,5 × the doubling
"longitudinal seams" are to extend beyond the "trans- plate thickness but shall not exceed the plating thick-
verse seams". Socket weldments are to be fully ness, see Fig. 19.4.
welded to the surrounding plating.
The welded transition at the end faces of the doubling
Regarding the increase of stress due to different thick- plates to the plating should form with the latter an
ness of plates see also Section 20, B.1.3. angle of 45° or less.
Chapter 1 Section 19 B Welded Joints I - Part 1
Page 19–4 GL 2012

2.6 Welding of cold formed sections, bending

radii
t

b/2 ~ 1,5 b 2.6.1 Wherever possible, welding should be

avoided at the cold formed sections with more than
5 % permanent elongation 2 and in the adjacent areas
r ³ 2t
2t

of structural steels with a tendency towards strain

b

r³

ageing.

2.6.2 Welding may be performed at the cold

formed sections and adjacent areas of hull structural
Fig. 19.4 Welding at the ends of doubling plates steels and comparable structural steels (e.g. those in
quality groups S...J... and S...K... to DIN EN 10025)
provided that the minimum bending radii are not less
2.4.4 Where proof of fatigue strength is required than those specified in Table 19.1.
(see Section 20), the configuration of the end of the
doubling plate shall conform to the selected detail
category. Table 19.1 Minimum inner bending radius r

Plate thickness Minimum inner bending

2.4.5 Doubling plates are not permitted in tanks for
t radius r
flammable liquids except collar plates and small dou-
blings for fittings like tank heating fittings or fittings to 4 mm 1,0 × t
for ladders.
to 8 mm 1,5 × t

2.5 Intersecting members, stress in the thick- to 12 mm 2,0 × t

ness direction to 24 mm 3,0 × t
over 24 mm 5,0 × t
2.5.1 Where, in the case of intersecting members,
plates or other rolled products are stressed in the
thickness direction by shrinking stresses due to the Note
welding and/or applied loads, suitable measures shall
be taken in the design and fabrication of the structures The bending capacity of the material may necessitate
to prevent lamellar tearing (stratified fractures) due to a larger bending radius.
the anisotropy of the rolled products.
2.6.3 For other steels and other materials, where
2.5.2 Such measures include the use of suitable applicable, the necessary minimum bending radius
weld shapes with a minimum weld volume and a shall, in case of doubt, be established by test. Proof
welding sequence designed to reduce transverse of adequate toughness after welding may be stipu-
shrinkage. Other measures are the distribution of the lated for steels with a yield strength of more than
stresses over a larger area of the plate surface by using 355 N/mm2 and plate thicknesses of 30 mm and above
a build-up weld or the joining together of several which have undergone cold forming resulting in 2 %
"fibres" of members stressed in the thickness direction or more permanent elongation.
as exemplified by the deck stringer/sheer strake joint
shown in Fig. 19.12. 2.7 Build-up welds on rudderstocks and pintles

2.5.3 In case of very severe stresses in the thick- 2.7.1 Wear resistance and/or corrosion resistant
ness direction due, for example, to the aggregate effect build-up welds on the bearing surfaces of rudder-
of the shrinkage stresses of bulky single or double- stocks, pintles etc. shall be applied to a thickened
bevel butt welds plus high applied loads, plates with collar exceeding by at least 20 mm the diameter of the
guaranteed through thickness properties (extra high- adjoining part of the shaft.
purity material and guaranteed minimum reductions in
area of tensile test specimens taken in thickness direc-
tion) 1 are to be used.

2 Elongation ε in the outer tensile-stressed zone

1 100
See the GL Rules for Steel and Iron Materials (II-1-2), Section ε = [% ]
1 and also Supply Conditions 096 for Iron and Steel Products, 1+ 2 r t
"Plate, strip and universal steel with improved resistance to
stress perpendicular to the product surface" issued by the Ger- r = inner bending radius [mm]
man Iron and Steelmakers' Association. t = plate thickness [mm]
I - Part 1 Section 19 B Welded Joints Chapter 1
GL 2012 Page 19–5

2.7.2 Where a thickened collar is impossible for 30° 30°

design reasons, the build-up weld may be applied to
the smooth shaft provided that relief-turning in accor-
dance with 2.7.3 is possible (leaving an adequate re-
sidual diameter). t t

2.7.3 After welding, the transition areas between

the welded and non-welded portions of the shaft shall 6 6
be relief-turned with large radii, as shown in Fig. 19.5,
to remove any base material whose structure close to Fig. 19.6 Single-side welds with permanent
the concave groove has been altered by the welding weld pool supports (backings)
operation and in order to effect the physical separation
of geometrical and metallurgical "notches". 3.1.4 The weld shapes illustrated in Fig. 19.7 shall
be used for clad plates. These weld shapes shall be
used in analogous manner for joining clad plates to
building weld on relief - turning (unalloyed and low alloyed) hull structural steels.
thickened collar after welding :4
.1
ax
m

60° 60°

Fig. 19.5 Build-up welds applied to rudderstocks

and pintles Welding the support material at an adequate disdance
(min. 2 mm) from the cladding material

3. Weld shapes and dimensions

3.1 Butt joints Grooving out the clad side of the plate

3.1.1 Depending on the plate thickness, the weld-

ing method and the welding position, butt joints shall
be of the square, V or double-V shape conforming to
the relevant standards (e.g. EN 22553/ISO 2533, Welding the clad side of the plate in at least two
ISO 9692 -1, -2, -3 or -4). Where other weld shapes passes, using special interpass electrodes where
are applied, these are to be specially described in the necessary
drawings. Weld shapes for special welding processes
such as single-side or electrogas welding shall have Fig. 19.7 Weld shapes for welding of clad plates
been tested and approved in the context of a welding
procedure test.
3.2 Corner, T and double-T (cruciform) joints
3.1.2 As a matter of principle, the rear sides of butt 3.2.1 Corner, T and double-T (cruciform) joints
joints shall be grooved and welded with at least one with complete union of the abutting plates shall be
capping pass. Exceptions to this rule, as in the case of made as single or double-bevel welds with a minimum
submerged-arc welding or the welding processes men- root face and adequate air gap, as shown in Fig. 19.8,
tioned in 3.1.1, require to be tested and approved in and with grooving of the root and capping from the
connection with a welding procedure test. The effec- opposite side.
tive weld thickness shall be deemed to be the plate
thickness, or, where the plate thicknesses differ, the
lesser plate thickness. Where proof of fatigue strength
is required (see Section 20), the detail category de-
2-3

2-3

pends on the execution (quality) of the weld.

°
45

°
45
»

3.1.3 Where the aforementioned conditions cannot

be met, e.g. where the welds are accessible from one
side only, the joints shall be executed as lesser bev- t t
elled welds with an open root and an attached or an
integrally machined or cast, permanent weld pool Fig. 19.8 Single and double-bevel welds with
support (backing) as shown in Fig. 19.6. full root penetration
Chapter 1 Section 19 B Welded Joints I - Part 1
Page 19–6 GL 2012

The effective weld thickness shall be assumed as the to the butt joints referred to in 3.1.3 using a weld pool
thickness of the abutting plate. Where proof of fatigue support (backing), or as single-side, single bevel welds
strength is required (see Section 20), the detail cate- in a manner similar to those prescribed in 3.2.2.
gory depends on the execution (quality) of the weld.

3.2.2 Corner, T and double-T (cruciform) joints 6 f

with a defined incomplete root penetration, as shown 45°
in Fig. 19.9, shall be made as single or double-bevel
welds, as described in 3.2.1, with a back-up weld but

2-3
45
without grooving of the root.

»
f f t
2-3

2-3
°
45

Fig. 19.11 Single-side welded T joints

45
»

The effective weld thickness shall be determined by

t t analogy with 3.1.3 or 3.2.2, as appropriate. Wherever
possible, these joints should not be used where proof
of fatigue strength is required (see Section 20).
Fig. 19.9 Single and double-bevel welds with
defined incomplete root penetration
3.2.5 Where corner joints are flush, the weld
The effective weld thickness may be assumed as the shapes shall be as shown in Fig. 19.12 with bevelling
thickness of the abutting plate t, where f is the incom- of at least 30° of the vertically drawn plates to avoid
plete root penetration of 0,2 t with a maximum of the danger of lamellar tearing. A similar procedure is
3 mm, which is to be balanced by equally sized double to be followed in the case of fitted T joints (uniting
fillet welds on each side. Where proof of fatigue three plates) where the abutting plate is to be socketed
strength is required (see Section 20), these welds are between the aligned plates.
to be assigned to type D1.

3.2.3 Corner, T and double-T (cruciform) joints »15° »15°

with both an unwelded root face c and a defined in- 2-3
2-3
complete root penetration f shall be made in accor-
dance with Fig. 19.10 »30° »30°

f/2 c f/2 c
f/2 f/2
2-3
°
45

2-3

°
°

5
45

»4

t t

Fig. 19.10 Single and double-bevel welds with Fig. 19.12 Flush fitted corner joints
unwelded root face and defined in
complete root penetration
3.2.6 Where, in the case of T joints, the direction of
The effective weld thickness shall be assumed as the the main stress lies in the plane of the horizontal plates
thickness of the abutting plate t minus (c + f), where f (e.g. the plating) shown in Fig. 19.13 and where the
is to be assigned a value of 0,2 t subject to a maximum connection of the perpendicular (web) plates is of
of 3 mm. Where proof of fatigue strength is required secondary importance, welds uniting three plates may
(see Section 20), these welds are to be assigned to be made in accordance with Fig. 19.13 (with the ex-
types D2 or D3. ception of those subjected mainly to dynamic loads).
For the root passes of the three plate weld sufficient
3.2.4 Corner, T and double-T (cruciform) joints penetration shall be achieved. Sufficient penetration
which are accessible from one side only may be made has to be verified in way of the welding procedure
in accordance with Fig. 19.11 in a manner analogous test.
I - Part 1 Section 19 B Welded Joints Chapter 1
GL 2012 Page 19–7

x³2a Note
2a
5° In the case of higher-strength aluminium alloys (e.g.
5° »1 »1 »1
»1 5 5 ° AlMg4,5Mn0,7), such an increment may be necessary
°
for cruciform joints subject to tensile stresses, as experi-
to ence shows that in the welding procedure tests the ten-
sile-shear strength of fillet welds (made with matching
filler metal) often fails to attain the tensile strength of
the base material. See also the GL Rules for Welding in
ts the Various Fields of Application (II-3-3), Section 1, F.
a 3.3.3 The throat thickness of fillet welds shall not
exceed 0,7 times the lesser thickness of the parts to be
Fig. 19.13 Welding together three plates connected (generally the web thickness). The mini-
mum throat thickness is defined by the expression:
The effective thickness of the weld connecting the
horizontal plates shall be determined in accordance t1 + t 2
a min = [mm],
with 3.2.2. The requisite "a" dimension is determined 3
by the joint uniting the vertical (web) plates and shall, but not less than 3 mm
where necessary, be determined in accordance with
Table 19.3 or by calculation as for fillet welds. t1 = lesser (e.g. the web) plate thickness [mm]
The following table shows reference values for the t2 = greater (e.g. the flange) plate thickness [mm]
design of three plate connections at rudders, steering
nozzle, etc. 3.3.4 It is desirable that the fillet weld section shall
be flat faced with smooth transitions to the base mate-
plating thickness rial. Where proof of fatigue strength is required (see
to [mm] ≤ 10 12 14 16 18 ≥ 20 Section 20), machining of the weld (grinding to re-
move notches) may be required depending on the
min. weld gap notch category. The weld should penetrate at least
6 7 8 10 11 12
x [mm] close to the theoretical root point.
min. web thickness
ts [mm] 10 12 14 16 18 20 3.3.5 Where mechanical welding processes are
used which ensure deeper penetration extending well
beyond the theoretical root point and where such
3.3 Fillet weld connections penetration is uniformly and dependably maintained
under production conditions, approval may be given
3.3.1 In principle fillet welds are to be of the dou- for this deeper penetration to be allowed for in deter-
ble fillet weld type. Exceptions to this rule (as in the mining the throat thickness. The effective dimension:
case of closed box girders and mainly shear stresses
2 emin
parallel to the weld) are subject to approval in each a deep = a + [mm]
individual case. The throat thickness "a" of the weld 3
(the height of the inscribed isosceles triangle) shall be shall be ascertained in accordance with Fig. 19.14 and
determined in accordance with Table 19.3 or by calcu- by applying the term "emin" to be established for each
lation according to C. The leg length of a fillet weld is
welding process by a welding procedure test. The
to be not less than 1,4 times the throat thickness "a".
throat thickness shall not be less than the minimum
For fillet welds at doubling plates, see 2.4.3; for the
throat thickness related to the theoretical root point.
welding of the deck stringer to the sheer strake, see
Section 7, A.2.1, and for bracket joints, see C.2.7.
e
e

a
a

3.3.2 The relative fillet weld throat thicknesses

specified in Table 19.3 relate to normal strength and
higher strength hull structural steels and comparable
em

structural steels. They may also be generally applied to

in

theoretical
high-strength structural steels and non-ferrous metals root centre
provided that the "tensile shear strength" of the weld
metal used is at least equal to the tensile strength of the Fig. 19.14 Fillet welds with increased penetration
base material. Failing this, the "a" dimension shall be
increased accordingly and the necessary increment 3.3.6 When welding on top of shop primers which
shall be established during the welding procedure test are particularly liable to cause porosity, an increase of
(see the GL Rules for Welding in the Various Fields the "a" dimension by up to 1 mm may be stipulated
of Application (II-3-3), Section 1, F.). Alternatively depending on the welding process used. This is spe-
proof by calculation taking account of the properties cially applicable where minimum fillet weld throat
of the weld metal may be presented. thicknesses are employed. The size of the increase
Chapter 1 Section 19 B Welded Joints I - Part 1
Page 19–8 GL 2012

shall be decided on a case by case basis considering a = required fillet weld throat thickness [mm] for
the nature and severity of the stressing following the a continuous weld according to Table 19.3 or
test results of the shop primer in accordance with the determined by calculation
GL Rules for Welding in the Various Fields of Appli-
cation (II-3-3), Section 3, F. This applies in analogous b = pitch = e + ℓ [mm]
manner to welding processes where provision has to
be made for inadequate root penetration. e = interval between the welds [mm]
ℓ = length of fillet weld [mm]
3.3.7 Strengthened filled welds continuous on both
sides are to be used in areas subjected to severe dy-
The pitch ratio b/ℓ should not exceed 5. The maximum
namic loads (e.g. for connecting the longitudinal and
transverse girders of the engine base to top plates unwelded length (b – ℓ with scallop and chain welds,
close to foundation bolts, see Section 8, C.3.2.5 and or b/2 – ℓ with staggered welds) should not exceed 25
Table 19.3), unless single or double-bevel welds are times the lesser thickness of the parts to be welded.
stipulated in these locations. In these areas the "a" The length of scallops should, however, not exceed
dimension shall equal 0,7 times the lesser thickness of 150 mm.
the parts to be welded.
3.3.10 Lap joints should be avoided wherever possi-
3.3.8 Intermittent fillet welds in accordance with ble and are not to be used for heavily loaded compo-
Table 19.3 may be located opposite one another (chain nents. In the case of components subject to low loads
intermittent welds, possibly with scallops) or may be lap joints may be accepted provided that, wherever pos-
staggered, see Fig. 19.15. In case of small sections sible, they are orientated parallel to the direction of the
other types of scallops may be accepted. main stress. The width of the lap shall be 1,5 t + 15 mm
(t = thickness of the thinner plate). Except where an-
In water and cargo tanks, in the bottom area of fuel oil other value is determined by calculation, the fillet
tanks and of spaces where condensed or sprayed water weld throat thickness "a" shall equal 0,4 times the
may accumulate and in hollow components (e.g. rud- lesser plate thickness, subject to the requirement that it
ders) threatened by corrosion, only continuous or shall not be less than the minimum throat thickness
intermittent fillet welds with scallops shall be used. required by 3.3.3. The fillet weld shall be continuous
This applies accordingly also to areas, structures or on both sides and shall meet at the ends.
spaces exposed to extreme environmental conditions
or which are exposed to corrosive cargo. 3.3.11 In the case of plug welding, the plugs should,
wherever possible, take the form of elongated holes
There shall be no scallops in areas where the plating is lying in the direction of the main stress. The distance
subjected to severe local stresses (e.g. in the bottom between the holes and the length of the holes may be
section of the fore ship) and continuous welds are to
determined by analogy with the pitch "b" and the fillet
be preferred where the loading is mainly dynamic.
weld length "ℓ" in the intermittent welds covered by
3.3.8. The fillet weld throat thickness "au" may be es-
[t] tablished in accordance with 3.3.9. The width of the
25

h
r³

holes shall be equal to at least twice the thickness of the

h
plate and shall not be less than 15 mm. The ends of the
f £ 4 £ 75 e £ 150 holes shall be semi-circular. Plates or sections placed
e underneath should at least equal the perforated plate in
thickness and should project on both sides to a distance
of 1,5 × the plate thickness subject to a maximum of 20
b=e+
mm. Wherever possible only the necessary fillet welds
e shall be welded, while the remaining void is packed
with a suitable filler. Lug joint welding is not allowed.

b=e+ 4. Welded joints of particular components

4.1 Welds at the ends of girders and stiffeners

Fig. 19.15 Scallop, chain and staggered welds
4.1.1 As shown in Fig. 19.16, the web at the end of
3.3.9 The throat thickness au of intermittent fillet intermittently welded girders or stiffeners is to be
welds is to be determined according to the selected continuously welded to the plating or the flange plate,
pitch ratio b/ℓ by applying the formula: as applicable, over a distance at least equal to the
depth "h" of the girder or stiffener subject to a maxi-
mum of 300 mm. Regarding the strengthening of the
b welds at the ends, extending normally over 0,15 of the
au = 1,1 ⋅ a   [mm]
ℓ span, see Table 19.3.
I - Part 1 Section 19 B Welded Joints Chapter 1
GL 2012 Page 19–9

no scallops 1.7h 4.2.2 Where the joint lies in the plane of the plate,
h h
it may conveniently take the form of a single-bevel
butt weld with fillet. Where the joint between the plate

20
h
and the section end overlaps, the fillet weld shall be
b b
b continuous on both sides and shall meet at the ends.
The necessary "a" dimension is to be calculated in
Fig. 19.16 Welds at the ends of girders and stiff- accordance with C.2.6. The fillet weld throat thickness
eners is not to be less than the minimum specified in 3.3.3.

4.1.2 The areas of bracket plates should be con- 4.3 Welded shaft bracket joints
tinuously welded over a distance at least equal to the
length of the bracket plate. Scallops are to be located 4.3.1 Unless cast in one piece or provided with
only beyond a line imagined as an extension of the integrally cast welding flanges analogous to those
free edge of the bracket plate. prescribed in 2.1.7 (see Fig. 19.18), strut barrel and
struts are to be connected to each other and to the shell
4.1.3 Wherever possible, the free ends of stiffeners
plating in the manner shown in Fig. 19.19.
shall abut against the transverse plating or the webs of
sections and girders so as to avoid stress concentrations
4.3.2 In the case of single-strut shaft brackets no
in the plating. Failing this, the ends of the stiffeners are
welding is to be performed on the arm at or close to
to be sniped and continuously welded over a distance of
the position of constraint. Such components shall be
at least 1,7 h subject to a maximum of 300 mm.
provided with integrally forged or cast welding
4.1.4 Where butt joints occur in flange plates, the flanges.
flange shall be continuously welded to the web on
both sides of the joint over a distance at least equal to [t]
the width of the flange.

4.2 Joints between section ends and plates

t
4.2.1 Welded joints connecting section ends and
plates may be made in the same plane or lapped.
Where no design calculations have been carried out or
stipulated for the welded connections, the joints may
be made analogously to those shown in Fig. 19.17.

h h
Fig. 19.18 Shaft bracket with integrally cast
welding flanges
d
d

2 [t]
[t']
³2d³20
0
d ³ 1.75 h d ³ h
t'

³ 0.67 h
³ 2 ³ 300
smoothly
rounded joint d
h h contours
1 1
d
d

t = plating thickness in accordance with Section 6, F. in [mm]

2
2
d
t' = +5 [mm] where d < 50mm
3
d ³ 1.5 h d ³ 1.5 h t' = 3 Öd [mm] where d ³ 50mm

³ 0.75 h ³ 0.5 h For shaft brackets of elliptically shaped cross section d may
1 1 be substituted by 2/3 d in the above formulae.
³ ³
2 0.33 h 2 0.75 h
Fig. 19.19 Shaft bracket without integrally cast
Fig. 19.17 Joints uniting section ends and plates welding flanges
Chapter 1 Section 19 C Welded Joints I - Part 1
Page 19–10 GL 2012

4.4 Rudder coupling flanges C. Stress Analysis

4.4.1 Unless forged or cast steel flanges with inte- 1. General analysis of fillet weld stresses
grally forged or cast welding flanges in conformity
with 2.1.7 are used, horizontal rudder coupling flanges 1.1 Definition of stresses
are to be joined to the rudder body by plates of gradu-
ated thickness and full penetration single or double- For calculation purposes, the following stresses in a
bevel welds as prescribed in 3.2.1, see Fig. 19.20. See fillet weld are defined (see also Fig. 19.22):
also Section 14, D.1.4 and D.2.4.
σ⊥ = normal stresses acting vertically to the direc-
4.4.2 Allowance shall be made for the reduced strength tion of the weld seam
of the coupling flange in the thickness direction see 1.5
and 2.5. In case of doubt, proof by calculation of the τ⊥ = shear stress acting vertically to the direction of
adequacy of the welded connection shall be produced. the weld seam
τII = shear stress acting in the direction of the weld
seam

tf

[t´] ³ 5 tf a
³ 300

[t] s^ tII
90° t^

t = plate thickness in accordance with

Section 14, E.3.1 [mm]
tf = actual flange thickness in [mm]
a
tf
t' = + 5 [mm] where tf < 50 mm Fig. 19.22 Stresses in a fillet weld
3
Normal stresses acting in the direction of the weld
t' = 3 t f [mm] where tf ≥ 50 mm seam need not be considered.
Fig. 19.20 Horizontal rudder coupling flanges For calculation purposes the weld seam area is a ⋅ ℓ.

4.4.3 The welded joint between the rudder stock Due to equilibrium conditions the following applies to
(with thickened collar, see 2.1.8) and the flange shall the flank area vertical to the shaded weld seam area:
be made in accordance with Fig. 19.21. τ⊥ = σ ⊥ .

D The equivalent stress is to be calculated by the follow-

ing formula:

R ³ 100 m σv = σ ⊥2 + τ⊥2 + τII2

m

1.2 Definitions
a =1 1
÷
b 3 5 a = throat thickness [mm]
ℓ = length of fillet weld [mm]
b

R
³4
5m
£ 8 mm

final machining m P = single force [N]

after welding
M = bending moment at the position considered [Nm]
Q = shear force at the point considered [N]
³ 30° a
S = first moment of the cross sectional area of the
2 mm

8 flange connected by the weld to the web in re-

R
lation to the neutral beam axis [cm3]
I = moment of inertia of the girder section [cm4]
Fig. 19.21 Welded joint between rudder stock and
coupling flange W = section modulus of the connected section [cm2]
I - Part 1 Section 19 C Welded Joints Chapter 1
GL 2012 Page 19–11

2. Determination of stresses P2

2.1 Fillet welds stressed by normal and shear P1

forces
Flank and frontal welds are regarded as being equal

e
for the purposes of stress analysis. In view of this,
normal and shear stresses are calculated as follows:

P
σ = τ = [N/mm2]
∑a⋅ℓ Fig. 19.24 Weld joint of a vertically mounted
lifting eye
Joint as shown in Fig. 19.23: P2 3 ⋅ P1 ⋅ e
τ⊥ = + [N/mm2]
2 ⋅ ℓ ⋅ a ℓ2 ⋅ a
– Stresses in frontal fillet welds:
P1
P1 τII = [N/mm2]
τ⊥ = [N/mm2] 2 ⋅ ℓ ⋅ a
2 ⋅ a ( ℓ1 + ℓ 2 )
Equivalent stress:
P2 P2 ⋅ e
τII = ± [N/mm2]
2 ⋅ a ( ℓ1 + ℓ 2 ) 2 ⋅ a ⋅ Ft σv = τ2⊥ + τII2

2.2 Fillet weld joints stressed by bending mo-

Ft = ( ℓ1 + a ) (ℓ2 + a ) [mm2]
ments and shear forces
The stresses at the fixing point of a girder are calcu-
lated as follows (in Fig. 19.25 a cantilever beam is
1 given as an example):
flank fillet weld
a
frontal fillet weld Q
a P1
2

a eo
z
M x x
a
eu
P2
e

Fig. 19.25 Fixing point of a cantilever beam

Fig. 19.23 Weld joint of an overlapped lifting eye
– Normal stress due to bending moment:
– Stresses in flank fillet welds:
M
P2 σ⊥ ( z) = z [N/mm2 ]
τ⊥ = [N/mm2] Is
2 ⋅ a ( ℓ1 + ℓ 2 )
M
σ⊥ max = eu [N/mm2 ], if eu > e0
P1 P2 ⋅ e Is
τII = ± [N/mm2]
2 ⋅ a ( ℓ1 + ℓ 2 ) 2 ⋅ a ⋅ Ft M
= e0 [N/mm2 ], if eu < e0
Is
ℓ1, ℓ2, e [mm]
– Shear stress due to shear force:
– Equivalent stress for frontal and flank fillet
welds: Q ⋅ Ss ( z )
τII (z) = [N/mm 2 ]
10 ⋅ Is ⋅ ∑ a
σv = τ2⊥ + τII2
Q ⋅ Ss max
τII max = [N/mm 2 ]
Joint as shown in Fig. 19.24: 20 ⋅ Is ⋅ a
Chapter 1 Section 19 C Welded Joints I - Part 1
Page 19–12 GL 2012

Is = moment of inertia of the welded joint 2.5 Intermittent fillet weld joints between web
related to the x-axis [cm4] and flange of bending girders
Ss(z) = the first moment of the connected Shear stress:
weld section at the point under con- Q ⋅ S ⋅ α b
[N/mm 2 ]
20 ⋅ I ⋅ a  ℓ 
sideration [cm3] τII =

z = distance from the neutral axis [cm] b = pitch

α = 1,1 stress concentration factor which takes
– Equivalent stress:
into account increases in shear stress at
It has to be proved that neither σ⊥max in the the ends of the fillet weld seam "ℓ"
region of the flange nor τIImax in the region of
the neutral axis nor the equivalent stress
σ v = σ 2⊥ + τII2 exceed the permitted limits
given in 2.8 at any given point. The equivalent
stress σv should always be calculated at the b
web-flange connection
Fig. 19.26 Intermittent fillet weld joint
2.3 Fillet weld joints stressed by bending and
torsional moments and shear forces The fillet weld thickness required is:
Regarding the normal and shear stresses resulting Q ⋅ S ⋅ 1,1  b 
a req [mm]
20 ⋅ I ⋅ τzul  ℓ 
from bending, see 2.2. Torsional stresses resulting =
from the torsional moment MT are to be calculated:

M T ⋅ 103 2.6 Fillet weld connections on overlapped

τT = [N/mm 2 ] profile joints
2 ⋅ a ⋅ Am
2.6.1 Profiles joined by means of two flank fillet
MT = torsional moment [Nm] welds (see Fig. 19.27):
Am = sectional area [mm2] enclosed by the weld Q
seam τ⊥ = [N/mm 2 ]
2 ⋅ a ⋅ d
The equivalent stress composed of all three compo- M ⋅ 103
nents (bending, shear and torsion) is calculated by τII = [N/mm 2 ]
means of the following formulae: 2 ⋅ a ⋅ c ⋅ d

σv = σ2⊥ + τII2 + τT2 [N/mm 2 ], The equivalent stress is:

2
where τII and τT have not the same direction σv = τ⊥ + τ2
II

2 c, d, ℓ1 , ℓ 2 , r [mm] see Fig. 19.27

σv = σ2⊥ + ( τII + τT ) [N/mm 2 ],
3 ℓ1 − ℓ 2
where τII and τT have the same direction c = r +
4
[ mm ]
2.4 Continuous fillet weld joints between web As the influence of the shear force can generally be
and flange of bending girders neglected, the required fillet weld thickness may be
determined by the following formula:
The stresses are to be calculated in way of maximum
shear forces. Stresses in the weld's longitudinal direc- W ⋅ 103
a req = [mm]
tion need not be considered. 1,5 ⋅ c ⋅ d
In the case of continuous double fillet weld connec-
tions the shear stress is to be calculated as follows: M Q
d
Q ⋅ S
τII = [N/mm 2 ]
20 ⋅ I ⋅ a
2

1
c

The fillet weld thickness required is:

r

Q ⋅ S
a req = [mm] Fig. 19.27 Profile joined by means of two flank
20 ⋅ I ⋅ τzul fillet joints
I - Part 1 Section 19 C Welded Joints Chapter 1
GL 2012 Page 19–13

2.6.2 Profiles joined by means of two flank and d

two frontal fillet welds (all round welding as shown d
M Q
in Fig. 19.28):
Q
τ⊥ = [N/mm2 ]
a ( 2 d + ℓ1 + ℓ 2 )

d
M ⋅ 103
τII = [N/mm2 ]
a ⋅ c ( 2d + ℓ1 + ℓ 2 )

The equivalent stress is:

Fig. 19.29 Bracket joint with idealized stress
σv = τ2⊥ + τII2 distribution resulting from moment M
and shear force Q
W ⋅ 103
a req = [mm] 2.8 Permissible stresses
 ℓ + ℓ2 
1,5 ⋅ c ⋅ d 1 + 1  The permissible stresses for various materials under
 2d  mainly static loading conditions are given in Table
19.2. The values listed for high strength steels, aus-
2.7 Bracket joints tenitic stainless steels and aluminium alloys are based
on the assumption that the strength values of the weld
Where profiles are joined to brackets as shown in Fig. metal used are at least as high as those of the parent
19.29, the average shear stress is: metal. If this is not the case, the "a"-value calculated
shall be increased accordingly (see also B.3.3.2).
3 ⋅ M ⋅ 103 Q
τ = + [N/mm2 ]
2 2 ⋅ a ⋅ d
4 ⋅ a ⋅ d

d = length of overlap [mm]

The required fillet weld thickness is to be calculated
from the section modulus of the profile as follows:

1 000 ⋅ W
a req = [mm]
d2

(The shear force Q has been neglected.)

M Q
d
2

1
c

Fig. 19.28 Profile joined by means of two flank

and two frontal fillet welds (all round
welding)
Chapter 1 Section 19 C Welded Joints I - Part 1
Page 19–14 GL 2012

Table 19.2 Permissible stresses in fillet weld seams

Permissible stresses [N/mm2]

ReH or Rp0,2
Material equivalent stress,
[N/mm2] shear stress
σvp, τp
normal strength
GL–A/B/D/E 235 115
hull structural steel
GL–A/D/E/F 32 315 145
higher strength
GL–A/D/E/F 36 355 160
structural steel
GL–A/D/E/F 40 390 175
S 460 460 200
high strength steels
S 690 685 290
1.4306/304 L 180
1.4404/316 L 190
1.4435/316 L 190
110
1.4438/317 L 195

austenitic and austenitic- 1.4541/321 205

ferritic stainless steels 1.4571/316 Ti 215
1.4406/316 LN 280
1.4429/316 LN 295 130
1.4439/317 LN 285
1.4462/318 LN 480 205

AlMg3/5754 80 1 35

AlMg4,5Mn0,7/5083 125 1 56
aluminium alloys
AlMgSi/6060 65 2 30

AlSi1MgMn/6082 110 2 45
1 Plates, soft condition
2 Sections, cold hardened
I - Part 1 Section 19 C Welded Joints Chapter 1
GL 2012 Page 19–15

Table 19.3 Fillet weld connections

Basic thickness of
fillet welds a/t0 1 Intermittent
Structural parts to be connected fillet welds
for double continuous
permissible 3
fillet welds 2
Bottom structures
transverse and longitudinal girders to each other 0,35 ×
– to shell and inner bottom 0,20 ×
centre girder to flat keel and inner bottom 0,40
transverse and longitudinal girders and stiffeners including shell plating in way of 0,30
bottom strengthening forward
machinery space
transverse and longitudinal girders to each other 0,35
– to shell and inner bottom 0,30
inner bottom to shell 0,40
sea chests, water side 0,50
inside 0,30
Machinery foundation
longitudinal and transverse girders to each other and to the shell 0,40
– to inner bottom and face plates 0,40
– to top plates 0,50 4
– in way of foundation bolts 0,70 4
– to brackets and stiffeners 0,30
longitudinal girders of thrust bearing to inner bottom 0,40
Decks
– to shell (general) 0,40
deckstringer to sheerstrake (see also Section 7, A.2) 0,50
Frames, stiffeners, beams etc.
general 0,15 ×
in peak tanks 0,30 ×
bilge keel to shell 0,15
Transverses, longitudinal and transverse girders
general 0,15 ×
within 0,15 of span from supports 0,25
cantilevers 0,40
pillars to decks 0,40
Bulkheads, tank boundaries, walls of superstructures and deckhouses
– to decks, shell and walls 0,40
Hatch coamings
– to deck (see also Section 17, C.1.8) 0,40
– to longitudinal stiffeners 0,30
Hatch covers
general 0,15 ×5
watertight or oiltight fillet welds 0,30
Rudder
plating to webs 0,25 ×
Stem
plating to webs 0,25 ×
1 t0 = Thickness of the thinner plate.
2 In way of large shear forces larger throat thicknesses may be required on the bases of calculations according to C.
3 For intermittent welding in spaces liable to corrosion B.3.3.8 is to be observed.
4 For plate thicknesses exceeding 15 mm single or double bevel butt joints with, full penetration or with defined incomplete root penetration
according to Fig. 19.9 to be applied.
5 excepting hatch covers above holds provided for ballast water.
I - Part 1 Section 20 A Fatigue Strength Chapter 1
GL 2012 Page 20–1

Section 20

Fatigue Strength

N = number of endured stress cycles accord-

in this Section are no changes in numbering
ing to S-N curve (= endured stress cycles
Preface under constant amplitude loading)
The proof of sufficient fatigue strength, i. e. the
∆σR = fatigue strength reference value of S-N
strength against crack initiation under dynamic loads
during operation, is useful for judging and reducing curve at 2 ⋅ 106 cycles of stress range
the probability of crack initiation of structural mem- [N/mm2] (= FAT class according to Table
bers during the design stage. 20.3)
Due to the randomness of the load process, the fm = correction factor for material effect
spreading of material properties and fabrication fac-
tors and to effects of ageing, crack initiation cannot be fR = correction factor for mean stress effect
completely excluded during later operation. Therefore fw = correction factor for weld shape effect
among other things periodical surveys are necessary.
fi = correction factor for importance of struc-
tural element

A. General ft = correction factor for thickness effect

fs = additional correction factor for structural
1. Definitions stress analysis
fn = factor considering stress spectrum and
s (+)
number of cycles for calculation of per-
missible stress range
∆σRc = corrected fatigue strength reference value
smax

of S-N curve at 2 ⋅ 106 stress cycles

Ds

[N/mm2]
sm

D = cumulative damage ratio

smin

time
2. Scope
(-)
2.1 A fatigue strength analysis is to be performed
Fig. 20.1 Dynamic load cycle for structures which are predominantly subjected to
cyclic loads. Items of equipment, e.g. hatch cover
∆σ = applied stress range (σmax – σmin) resting pads or equipment holders, are thereby also to
[N/mm2], see also Fig. 20.1 be considered. The notched details i. e. the welded
joints as well as notches at free plate edges are to be
σmax = maximum upper stress of a stress cycle considered individually. The fatigue strength assess-
[N/mm2] ment is to be carried out either on the basis of a per-
missible peak stress range for standard stress spectra,
σmin = maximum lower stress of a stress cycle see B.2.1 or on the basis of a cumulative damage ratio,
[N/mm2] see B.2.2.
∆σmax = applied peak stress range within a stress 2.2 No fatigue strength analysis is required if the
range spectrum [N/mm2] peak stress range due to dynamic loads in the seaway
σm = mean stress (σmax/2 + σmin/2) [N/mm2] (stress spectrum A according to 2.4) and/or due to
changing draught or loading conditions, respectively,
∆σp = permissible stress range [N/mm2] fulfils the following conditions:

∆τ = Corresponding range for shear stress – peak stress range only due to seaway-induced
[N/mm2] dynamic loads:

n = number of applied stress cycles ∆σmax ≤ 2,5 ∆σR

Chapter 1 Section 20 A Fatigue Strength I - Part 1
Page 20–2 GL 2012

– sum of the peak stress ranges due to seaway- In case of only seaway-induced stresses, for a design
induced dynamic loads and due to changes of lifetime of about 20 years normally the stress range
draught or loading condition, respectively: spectrum A is to be assumed with a number of cycles
nmax = 5 ⋅ 107.
∆σmax ≤ 4, 0 ∆σR
For design lifetime of 30 years the number of cycles
nmax = 7,5 ⋅ 107 is to be assumed.
Note
The maximum and minimum stresses result from the
For welded steel structures of FAT class 80 or higher
maximum and minimum relevant seaway-induced load
a fatigue strength analysis is required only in case of
effects. The different load-effects for the calculation of
extraordinary high dynamic stresses.
∆σmax are, in general, to be superimposed conserva-
tively. Table 20.1 shows examples for the individual
2.3 The rules are applicable to constructions loads which have to be considered in normal cases.
made of normal and higher-strength hull structural
steels according to Section 2, B. as well as aluminium Under extreme seaway conditions stress ranges exceed-
alloys. Other materials such as cast steel can be treated ing ∆σmax occur (see Section 5, C.8.). These stress
in an analogous manner by using appropriate design ranges, which load cycles are to be generally assumed
S-N curves. with n < 104, can be neglected regarding the fatigue
life, when the stress ranges ∆σmax derived from loads
Low cycle fatigue problems in connection with exten- according to Table 20.1 are assigned to the spectrum A.
sive cyclic yielding have to be specially considered.
When applying the following rules, the calculated For ships of unconventional hull shape and for ships for
nominal stress range should not exceed 1,5 times the which a special mission profile applies, a stress range
yield strength. In special cases the fatigue strength spectrum deviating from spectrum A may be applied
analysis may be performed by considering the local which may be evaluated by the spectral method.
elasto-plastic stresses.
Other significant fluctuating stresses, e.g. in longitudi-
nals due to deflections of supporting transverses (see
2.4 The stress ranges ∆σ which are to be ex- Section 9, B.3.5 on this), in longitudinal and trans-
pected during the service life of the ship or structural verse structures due to torsional deformations (see for
component, respectively, may be described by a stress this also Section 5, F.1.1) as well as additional stresses
range spectrum (long-term distribution of stress range) due to the application of non-symmetrical sections,
Fig. 20.2 shows three standard stress range spectra A, have to be considered, see Section 3, L.
B and C, which differ from each other in regard to the
distribution of stress range ∆σ as a function of the
2.5 Additional stress cycles resulting from chang-
number of load cycles.
ing mean stresses, e.g. due to changing loading condi-
tions or draught, need generally not be considered as
C 1,0 long as the seaway-induced stress ranges are deter-
mined for the loading condition being most critical
with respect to fatigue strength and the maximum
B change in mean stress is less than the maximum sea-
Dsmax

A way-induced stress range.

0,5
Ds

Larger changes in mean stress are to be included in the

stress range spectrum by conservative super position-
ing of the largest stress ranges (e.g. in accordance with
the "rain flow counting method"). If nothing else is
0 specified, 103 load cycles have to be assumed for
log 1 log n max changes in loading condition or draught.

log n 2.6 The fatigue strength analysis is, depending on

A : straight-line spectrum (typical stress range the detail considered, based on one of the following
spectrum of seaway-induced stress ranges) types of stress:

B : parabolic spectrum (approximated normal – For notches of free plate edges the notch stress
distribution of stress range Ds acc. DIN σk, determined for linear-elastic material behav-
15018) iour, is relevant, which can normally be calcu-
lated from a nominal stress σn and a theoretical
C : rectangular spectrum (constant stress range stress concentration factor Kt. Values for Kt are
within the whole spectrum; typical spectrum
given in Section 3, Fig. 3.8 and 3.9 for different
of engine- or propeller-excited stress ranges)
types of cut-outs. The fatigue strength is deter-
mined by the FAT class (∆σR) according to Ta-
Fig. 20.2 Standard stress range spectra A, B and C ble 20.3, type E2 and E3.
I - Part 1 Section 20 A Fatigue Strength Chapter 1
GL 2012 Page 20–3

Table 20.1 Maximum and minimum value for seaway induced cyclic loads

Load Maximum load Minimum load

Vertical bending moments MSW + MST + f Q ⋅ M WVhog MSW + MST + f Q ⋅ M WVsag

(Section 5, B.) 1
Vertical bending moments MSW + MST MSW + MST
and horizontal wave bending
moments 1 (Section 5, B.) (
+ fQ ⋅ 0,6 ⋅ MWVhog + MWH ) (
+ fQ ⋅ 0,6 ⋅ MWVsag − MWH )
f F ⋅ {M SW + MST fF ⋅ {MSW + MST
Vertical bending moments, + f Q ⋅ ( 0, 43 + C ) ⋅ M WVhog + fQ ⋅ ( 0, 43 + C ⋅ ( 0,5 − C) ) ⋅ MWVhog
horizontal wave bending
moments and torsional + M WH + M WT ]} + C ⋅ ( 0,43 + C) ⋅ MWVsag − MWH − MWT  }
moments 1
2
(Section 5, B.) x 
C =  − 0,5 
L 
Loads on weather decks 2 pD 0
(Section 4, B.1.)
Loads on ship's sides 2, 4  z  z
10 ( T − z ) + p0 ⋅ cF 1 +  10 ( T − z ) − p0 ⋅ c F  1 + 
– below T  T  T
– above T 20 but ≥ 0
p0 ⋅ cF
(Section 4, B.2.) 10 + z − T 0
Loads on ship's bottom 2, 4
(Section 4, B.3.) 10 T + p0 ⋅ cF 10 T − p0 ⋅ cF

Liquid pressure upright 4 9,81⋅ h1 ⋅ ρ (1 + av ) + 100 pv 9,81 ⋅ h1 ⋅ ρ (1 − a v ) + 100 p v

in completely
filled tanks 9,81 ⋅ ρ [h1 ⋅ cos ϕ 9,81 ⋅ ρ [h1 ⋅ cos ϕ + ( 0,3 ⋅ b − y )
(Section 4, D.1.) heeled
+ ( 0,3 ⋅ b + y ) sin ϕ] + 100 p v ⋅ sin ϕ] + 100 p v but ≥ 100 p v

p (1 + a v ) p (1 − a v )
Loads due to cargo 5
p ⋅ a x ⋅ 0, 7 − p ⋅ a x ⋅ 0, 7
(Section 4, C.1.1 and E.1)
p ⋅ a y ⋅ 0,7 − p ⋅ a y ⋅ 0, 7
Loads due to friction
forces 3 Ph – Ph
(Section 17, B.4.5.5)
Loads due to rudder forces 3 CR – CR
(Section 14, B.) QR – QR
1 Maximum and minimum load are to be so determined that the largest applied stress range ∆σ as per Figure 20.1 at conservative mean
stress is obtained having due regard to the sign (plus, minus). For fF, fQ see Section 5, D.1.
2 With probability factor f for calculation of p according to Section 4, A.2.2, however:
0
f = 1,0 for stiffeners if no other cyclic load components are considered
3 In general, the largest load is to be taken in connection with the load spectrum B without considering further cyclic loads.

For hatch cover supports the following load spectra are to be used:
– spectrum A for non-metallic, frictionless material on steel contact
– spectrum B for steel on steel contact
4 Assumption of conservative superpositioning of sea and tank pressures within 0,2 < x/L ≤ 0,7: Where appropriate, proof is to be furnished
for Tmin.
5 Probability factor f = 1,0 used for determination of a and further calculation of a and a according to Section 4, E.1.
Q 0 x y
Chapter 1 Section 20 B Fatigue Strength I - Part 1
Page 20–4 GL 2012

– For welded joints the fatigue strength analysis is cluding subsequent quality control, and definition of
normally based on the nominal stress σn at the nominal stress. Table 20.3 shows the detail classifi-
structural detail considered and on an appropri- cation based on recommendations of the International
ate detail classification as given in Table 20.3, Institute of Welding (IIW) giving the FAT class (∆σR)
which defines the FAT class (∆σR). for structures made of steel or aluminium alloys (Al).
– For those welded joints, for which the detail In Table 20.4 ∆σR-values for steel are given for some
classification is not possible or additional intersections of longitudinal frames of different shape
stresses occur, which are not or not adequately and webs, which can be used for the assessment of the
considered by the detail classification, the fatigue longitudinal stresses.
strength analysis may be performed on the basis
of the structural stress σs in accordance with C. It has to be noted that some influence parameters
cannot be considered by the detail classification and
that a large scatter of fatigue strength has therefore to
3. Quality requirements (fabrication toler-
be expected.
ances)

3.1 The detail classification of the different 1.2 Details which are not contained in Table 20.3
welded joints as given in Table 20.3 is based on the may be classified either on the basis of local stresses
assumption that the fabrication of the structural detail in accordance with C. or, else, by reference to pub-
or welded joint, respectively, corresponds in regard to lished experimental work or by carrying out special
external defects at least to quality group B according fatigue tests, assuming a sufficiently high confidence
to DIN EN ISO 5817 and in regard to internal defects level (see 3.1) and taking into account the correction
at least to quality group C. Further information about factors as given in C.4.
the tolerances can also be found in the GL Rules for
Design, Fabrication and Inspection of Welded Joints 1.3 Regarding the definition of nominal stress,
(II-3-2). the arrows in Table 20.3 indicate the location and
direction of the stress for which the stress range is to
3.2 Relevant information have to be included in be calculated. The potential crack location is also
the manufacturing document for fabrication. If it is not shown in Table 20.3. Depending on this crack loca-
possible to comply with the tolerances given in the tion, the nominal stress range has to be determined
standards, this has to be accounted for when designing by using either the cross sectional area of the parent
the structural details or welded joints, respectively. In metal or the weld throat thickness, respectively.
special cases an improved manufacture as stated in 3.1 Bending stresses in plate and shell structures have to
may be required, e.g. stricter tolerances or improved be incorporated into the nominal stress, taking the
weld shapes, see also B.3.2.4. nominal bending stress acting at the location of crack
initiation.
3.3 The following stress increase factors km for
considering significant influence of axial and angular Note
misalignment are already included in the fatigue
strength reference values ∆σR (Table 20.3): The factor Ks for the stress increase at transverse butt
welds between plates of different thickness (see type
km = 1,15 butt welds (corresponding type A1, A2, A11) A5 in Table 20.3) can be estimated in a first approxi-
mation as follows:
= 1,30 butt welds (corresponding type A3–A10)
t2
= 1,45 cruciform joints (corresponding type D1– D5) Ks =
t1
= 1,25 fillet welds on one plate surface
(corresponding type C7, C8) t1 = smaller plate thickness
Other additional stresses need to be considered sepa- t2 = larger plate thickness
rately.
Additional stress concentrations which are not charac-
teristic of the FAT class itself, e.g. due to cut-outs in
B. Fatigue Strength Analysis for Free Plate the neighbourhood of the detail, have also to be incor-
Edges and for Welded Joints Using Detail porated into the nominal stress.
Classification
1.4 In the case of combined normal and shear
1. Definition of nominal stress and detail stress the relevant stress range is to be taken as the
classification for welded joints range of the principal stress at the potential crack
location which acts approximately perpendicular
1.1 Corresponding to their notch effect, welded (within ± 45°) to the crack front as shown in Table
joints are normally classified into detail categories con- 20.3 as long as it is larger than the individual stress
sidering particulars in geometry and fabrication, in- components.
I - Part 1 Section 20 B Fatigue Strength Chapter 1
GL 2012 Page 20–5

1.5 Where solely shear stresses are acting the life is to be established (see A.2.4) and the cumulative
largest principal stress σ1 = τ may be used in combi- damage ratio D is to be calculated as follows:
nation with the relevant FAT class. I
D = ∑ ( ni Ni )
2. Permissible stress range for standard i =1
stress range spectra or calculation of the
cumulative damage ratio I = total number of blocks of the stress range
spectrum for summation (normally I ≥ 20)
2.1 For standard stress range spectra according to ni = number of stress cycles in block i
Fig. 20.2, the permissible peak stress range can be
calculated as follows: Ni = number of endured stress cycles determined
from the corrected design S-N curve (see 3.)
∆σ p = f n ⋅ ∆σRc taking ∆σ = ∆σi
∆σRc = FAT class or fatigue strength reference value, ∆σi = stress range of block i
respectively, corrected according to 3.2
fn = factor as given in Table 20.2 To achieve an acceptable high fatigue life, the cumula-
tive damage ratio should not exceed D = 1.
The peak stress range of the spectrum shall not exceed
the permissible value, i.e. If the expected stress range spectrum can be superim-
posed by two or more standard stress spectra according
to A.2.4, the partial damage ratios Di due to the indi-
∆σmax ≤ ∆σp
vidual stress range spectra can be derived from Table
20.2. In this case a linear relationship between number
2.2 If the fatigue strength analysis is based on the of load cycles and cumulative damage ratio may be
calculation of the cumulative damage ratio, the stress assumed. The numbers of load cycles given in Table
range spectrum expected during the envisaged service 20.2 apply for a cumulative damage ratio of D = 1.

Table 20.2 Factor fn for the determination of the permissible stress range for standard stress range spectra

Welded Joints Plates Edges

Stress
range (mo = 3) Type E1 (mo = 5) Type E2, E2a (mo = 4) Type E3 (mo = 3,5)
spec- nmax = nmax = nmax = nmax =
trum
103 105 5 ⋅ 107 108 3 ⋅ 108 103 105 5 ⋅ 107 108 3 ⋅ 108 103 105 5 ⋅ 107 108 3 ⋅ 108 103 105 5 ⋅ 107 108 3 ⋅ 108

(8,63) (10,3)
A (17,2) 3,53 3,02 2,39 (8,1) 3,63 3,32 2,89 3,66 3,28 2,76 3,65 3,19 2,62
(9,20)3 (12,2)2

(10,30) 5,50 6,6

B (9,2) 1,67 1,43 1,15 (9,5) 5,0 1,95 1,78 1,55 1,86 1,65 1,40 1,78 1,55 1,28
(11,20)3 5,903 7,52

0,424 0,369 0,296 0,606 0,561 0,500 0,532 0,482 0,411 0,483 0,430 0,358
C (12,6) 2,71 (4,57) 1,82 (4,57) 1,82 (4,57) 1,82
0,5431 0,5261 0,5011 0,6731 0,6531 0,6211 0,6211 0,6021 0,5731 0,5871 0,5691 0,5411

For definition of type E1 to type E3 see Table 20.3

For definition of mo see 3.1.2
The values given in parentheses may be applied for interpolation.
For interpolation between any pair of values (nmax1; fn1) and (nmax2; fn2), the following formula may be applied in the case of stress spectrum
A or B:

log ( f n2 f n1 )
log fn = log f n1 + log ( n max n max1 )
log ( n max 2 n max1 )

For the stress spectrum C intermediate values may be calculated according to 3.1.2 by taking N = nmax and fn = ∆σ/∆σR.

1 f for non-corrosive environment, see also 3.1.4.

n
2 for ∆σ = 100 [N/mm2]
R
3 for ∆σ = 140 [N/mm2]
R
Chapter 1 Section 20 B Fatigue Strength I - Part 1
Page 20–6 GL 2012

3. Design S-N curves = 3 for welded joints

3.1 Description of the design S-N curves = 3,5 ÷ 5 for free plate edges
(see Fig. 20.4)
3.1.1 The design S-N curves for the calculation of
the cumulative damage ratio according to 2.2 are The S-N curve for FAT class 160 forms the upper limit
shown in Fig. 20.3 for welded joints at steel and in for the S-N curves of free edges of steel plates with
Fig. 20.4 for notches at plate edges of steel plates. detail categories 100 – 150 in the range of low stress
For aluminium alloys (Al) corresponding S-N curves cycles, see Fig. 20.4. The same applies accordingly to
apply with reduced reference values of the S-N FAT classes 32 – 40 of aluminium alloys with an upper
curves (FAT classes) acc. to Table 20.3. The S-N limit of FAT 71, see type E1 in Table 20.3.
curves represent the lower limit of the scatter band of
95 % of all test results available (corresponding to 3.1.3 For structures subjected to variable stress
97,5 % survival probability) considering further det- ranges, the S-N curves shown by the solid lines in Fig.
rimental effects in large structures. 20.3 and Fig. 20.4 have to be applied (S-N curves of
type "M"), i.e.
To account for different influence factors, the design
S-N curves have to be corrected according to 3.2. m = m0 for N ≤ 107 (Q ≤ 0)

3.1.2 The S-N curves represent section-wise linear m = 2 ⋅ m0 – 1 for N > 107 (Q > 0)
relationships between log (∆σ) and log (N):
3.1.4 For stress ranges of constant magnitude (stress
log (N) = 7, 0 + m ⋅ Q range spectrum C) in non-corrosive environment from
N = 1 ⋅ 107 the S-N curves of type "O" in Fig. 20.3 and
Q = log (∆σR/∆σ) – 0,69897/m0 20.4 can be used, thus:
m = slope exponent of S-N curve, see 3.1.3 and
m = m0 for N ≤ 107 (Q ≤ 0)
3.1.4
m0 = inverse slope in the range N ≤ 1 ⋅ 107 m = 22 for N > 107 (Q > 0)

1000
Ds [N/mm2]

FAT class
( N = 2·106 )

125
100
80 112
100 63 90 "O" m=5
50 71
40 56
45
36

m0 = 3

"M"
10
1·107

104 105 106 107 108 N 5·108

Fig. 20.3 S-N curves for welded joints at steel

I - Part 1 Section 20 B Fatigue Strength Chapter 1
GL 2012 Page 20–7

1000
Ds [N/mm2]

m0 = 5 FAT class
m0 = 4 ( N = 2·106 )
m=9
140 160
100 "O" m=7
125
100
m0 = 3.5

m=6
"M"

1·107
10
104 105 106 107 108 5·108
N

Fig. 20.4 S-N curves for notches at plate edges of steel plates

3.2 Correction of the reference value of the f R = 1, 0

design S-N curve
– in the range of alternating stresses, i.e.
3.2.1 A correction of the reference value of the S-N
curve (FAT class) is required to account for additional ∆σ max ∆σmax
influence factors on fatigue strength as follows: − ≤ σm ≤
2 2
 2 ⋅ σm 
∆σRc = f m ⋅ f R ⋅ f w ⋅ fi ⋅ f t ⋅ ∆σR f R = 1 + c 1 − 
 ∆σ max 
fm, fR, fw, fi, ft defined in 3.2.2 – 3.2.6
– in the range of compressive pulsating stresses,
For the description of the corrected design S-N curve, i.e.
the formulae given in 3.1.2 may be used by replacing ∆σmax
∆σR by ∆σRc. σm ≤ −
2
fR = 1+ 2⋅c
3.2.2 Material effect (fm)
c = 0 for welded joints subjected to constant
For welded joints it is generally assumed that the stress cycles (stress range spectrum C)
fatigue strength is independent of steel strength, i.e.:
= 0,15 for welded joints subjected to variable
f m = 1, 0 stress cycles (corresponding to stress
range spectrum A or B)
For free edges at steel plates the effect of the mate-
rial's yield strength is accounted for as follows: = 0,3 for unwelded base material

R eH − 235 3.2.4 Effect of weld shape (fw)

fm = 1 +
1200 In normal cases:
For aluminium alloys, fm = 1 generally applies.
f w = 1, 0
3.2.3 Effect of mean stress (fR) A factor fw > 1,0 applies for welds treated e.g. by grind-
The correction factor is calculated as follows: ing. Grinding removes surface defects such as slag in-
clusions, porosity and crack-like undercuts, to achieve
– in the range of tensile pulsating stresses, i.e. a smooth transition from the weld to the base material.
Final grinding shall be performed transversely to the
∆σ max weld direction. The depth should be about 0,5 mm
σm ≥
2 larger than the depth of visible undercuts.
Chapter 1 Section 20 C Fatigue Strength I - Part 1
Page 20–8 GL 2012

For ground weld toes of fillet and K-butt welds ma- 3.2.6 Plate thickness effect
chined by:
In order to account for the plate thickness effect, ap-
– disc grinder: fw = 1,15 plication of the reduction factor ft is required by GL
– burr grinder: fw = 1,30 for butt welds oriented transversely to the direction of
applied stress for plate thicknesses t > 25 mm.
Premise for this is that root and internal failures can be
excluded. Application of toe grinding to improve fatigue n
 25 
strength is limited to following details of Table 20.3: ft =  
 t 
– butt welds of type A2, A3 and A5 if they are
ground from both sides n = 0,17 as welded
– non-load-carrying attachments of type C1, C2,
= 0,10 toe-ground
C5 and C6 if they are completed with a full pene-
tration weld For all other weld connections consideration of the
– transverse stiffeners of type C7 thickness effect may be required subject to agreement
with GL.
– doubling plates of type C9 if the weld throat thick-
ness acc. to Section 19 was increased by 30 %
– cruciform and T-joints of type D1 with full pene-
C. Fatigue Strength Analysis for Welded
tration welds
Joints Based on Local Stresses
The corrected FAT class that can be reached by toe
grinding is limited for all types of welded connections
1. Alternatively to the procedure described in
of steel to fw ⋅ ∆σR = 100 N/mm2 and of aluminium to
the preceding paragraphs, the fatigue strength analysis
fw ⋅ ∆σR = 40 N/mm2. for welded joints may be performed on the basis of
local stresses. For common plate and shell structures
For butt welds ground flush the corresponding refer-
in ships the assessment based on the so-called struc-
ence value of the S-N curve (FAT class) has to be
chosen, e.g. type A1, A10 or A12 in Table 20.3. tural (or hot-spot) stress σs is normally sufficient.

For endings of stiffeners or brackets, e.g. type C2 in The structural stress is defined as the stress being
Table 20.3, which have a full penetration weld and are extrapolated to the weld toe excluding the local stress
completely ground flush to achieve a notch-free transi- concentration in the local vicinity of the weld, see Fig.
tion, the following factor applies: 20.5.
f w = 1, 4
ss s
The assessment of a local post-weld treatment of the
weld surface and the weld toe by other methods e.g. ultra-
sonic impact treatment has to be agreed on in each case.

3.2.5 Influence of importance of structural ele-

ment (fi)
In general the following applies:
fi = 1, 0 Fig. 20.5 Structural stress

For secondary structural elements failure of which 2. The structural stress can be determined by
may cause failure of larger structural areas, the correc- measurements or numerically e.g. by the finite ele-
tion factor fi is to be taken as: ment method using shell or volumetric models under
the assumption of linear stress distribution over the
fi = 0,9 plate thickness. Normally the stress is extrapolated
linearly to the weld toe over two reference points
For notches at plate edges in general the following which are located 0,5 and 1,5 × plate thickness away
correction factor is to be taken which takes into ac- from the weld toe. In some cases the structural stress
count the radius of rounding:
can be calculated from the nominal stress σn and a
fi = 0,9 + 5 r ≤ 1, 0 structural stress concentration factor Ks, which has
been derived from parametric investigations using the
r = notch radius [mm]; for elliptical roundings methods mentioned. Parametric equations should be
the mean value of the two main half axes may used with due consideration of their inherent limita-
be taken. tions and accuracy.
I - Part 1 Section 20 C Fatigue Strength Chapter 1
GL 2012 Page 20–9

3. For the fatigue strength analysis based on 1

structural stress, the S-N curves shown in Fig. 20.3 fs =
∆σs,b
apply with the following reference values: k 'm − (k 'm − 1)
∆σs,max
∆σR = 100 (resp. 40 for Al):
∆σs,max = applied peak stress range within a stress
for the butt welds types A1 –A 6 and for K-butt range spectrum
welds with fillet welded ends, e.g. type D1 in
Table 20.3, and for fillet welds which carry no ∆σs,b = bending portion of ∆σs,max
load or only part of the load of the attached
k 'm = km – 0,05
plate, type C1- C9 in Table 20.3
km = stress increase factor due to misalignments
∆σR = 90 (resp. 36 for Al): under axial loading, at least km acc. A.3.3.
for fillet welds, which carry the total load of the
The permissible stress range or cumulative damage ratio,
attached plate, e.g. type D2 in Table 20.3.
respectively, has to be determined according to B.2.
In special cases, where e.g. the structural stresses are
obtained by non-linear extrapolation to the weld toe 5. In addition to the assessment of the structural
and where they contain a high bending portion, in- stress at the weld toe, the fatigue strength with regard
creased reference values of up to 15 % can be allowed. to root failure has to be considered by analogous ap-
plication of the respective FAT class, e.g. type D3 of
Table 20.3.
4. The reference value ∆σRc of the corrected S-N
curve is to be determined according to B.3.2, taking In this case the relevant stress is the stress in the weld
into account the following additional correction factor cross section caused by the axial stress in the plate
which describes influencing parameters not included in perpendicular to the weld. It is to be converted at a
the calculation model such as e.g. misalignment: ratio of t/2a.
Chapter 1 Section 20 C Fatigue Strength I - Part 1
Page 20–10 GL 2012

Table 20.3 Catalogue of details

A. Butt welds, transverse loaded

Joint configuration showing FAT class

Type ∆σR
mode of fatigue cracking Description of joint
No.
and stress σ considered
Steel Al
Transverse butt weld ground flush to plate,
A1 112 45
100 % NDT (Non-Destructive Testing)
Transverse butt weld made in shop in flat position,
A2 max. weld reinforcement 1 mm + 0,1 × weld 90 36
width, smooth transitions, NDT
Transverse butt weld not satisfying conditions for
A3 80 32
joint type No. A2, NDT

Transverse butt weld on backing strip or three- 71 25

A4 plate connection with unloaded branch

Butt weld, welded on ceramic backing, root crack 80 28

Transverse butt welds between plates of different
widths or thickness, NDT
as for joint type No. A2, slope 1 : 5 90 32
as for joint type No. A2, slope 1 : 3 80 28
as for joint type No. A2, slope 1 : 2 71 25
as for joint type No. A3, slope 1 : 5 80 25
A5 as for joint type No. A3, slope 1 : 3 71 22
as for joint type No. A3, slope 1 : 2 63 20
For the third sketched case the slope results from
the ratio of the difference in plate thicknesses to
the breadth of the welded seam.
Additional bending stress due to thickness change
to be considered, see also B.1.3.
Transverse butt welds welded from one side
without backing bar, full penetration
root controlled by NDT 71 28
A6
not NDT 36 12
For tubular profiles ∆σR may be lifted to the next
higher FAT class.
Partial penetration butt weld; the stress is to be
A7 related to the weld throat sectional area, weld 36 12
overfill not to be taken into account
I - Part 1 Section 20 C Fatigue Strength Chapter 1
GL 2012 Page 20–11

Table 20.3 Catalogue of details (continued)

A. Butt welds, transverse loaded

Joint configuration showing FAT class

Type ∆σR
mode of fatigue cracking Description of joint
No.
and stress σ considered
Steel Al

Full penetration butt weld at crossing flanges

Welded from both sides.
A8 50 18

Full penetration butt weld at crossing flanges

Welded from both sides

w (t) b
Cutting edges in the quality according to type E2
A9 63 22
or E3
F
Connection length w ≥ 2b σnomin al =
b⋅t

Full penetration butt weld at crossing flanges

Welded from both sides, NDT, weld ends ground,
butt weld ground flush to surface
A10 w (t) b Cutting edges in the quality according to type E2 80 32
or E3 with ∆σR = 125
F
Connection length w ≥ 2b σnomin al =
b⋅t

Full penetration butt weld at crossing flanges 90 36

welded from both sides made in shop at flat
R

position, radius transition with R ≥ b

A11 b Weld reinforcement ≤ 1 mm + 0,1 x weld width,
smooth transitions, NDT, weld ends ground
Cutting edges in the quality according to type E2
or E3 with ∆σR = 125

Full penetration butt weld at crossing flanges, 100 40

edges broken
or rounded radius transition with R ≥ b
R

Welded from both sides, no misalignment,

A12 b 100 % NDT, weld ends ground, butt weld ground
flush to surface
Cutting edges broken or rounded according to
type E2
Chapter 1 Section 20 C Fatigue Strength I - Part 1
Page 20–12 GL 2012

Table 20.3 Catalogue of details (continued)

B. Longitudinal load-carrying weld

Joint configuration showing FAT class

Type ∆σR
mode of fatigue cracking Description of joint
No.
and stress σ considered
Steel Al

Longitudinal butt welds

both sides ground flush parallel to load direction 125 50
B1
without start/stop positions, NDT 125 50
with start/stop positions 90 36

Continuous automatic longitudinal fully

penetrated K-butt without stop/start positions 125 50
B2 (based on stress range in flange adjacent to weld)

Continuous automatic longitudinal fillet weld

penetrated K-butt weld without stop/start 100 40
B3 positions (based on stress range in flange adjacent
to weld)

Continuous manual longitudinal fillet or butt weld

90 36
(based on stress range in flange adjacent to weld)
B4

Intermittent longitudinal fillet weld (based on

stress range in flange at weld ends)
B5 In presence of shear τ in the web, the FAT class 80 32
has to be reduced by the factor (1 – ∆τ / ∆σ), but
not below 36 (steel) or 14 (Al).
Longitudinal butt weld, fillet weld or intermittent
fillet weld with cut outs (based on stress range in 71 28
flange at weld ends)
If cut out is higher than 40 % of web height 63 25
In presence of shear τ in the web, the FAT class
B6
has to be reduced by the factor (1 – ∆τ / ∆σ), but
not below 36 (steel) or 14 (Al).
Note
For Ω-shaped scallops, an assessment based on
local stresses in recommended.
I - Part 1 Section 20 C Fatigue Strength Chapter 1
GL 2012 Page 20–13

Table 20.3 Catalogue of details (continued)

C. Non-load-carrying attachments
Joint configuration showing FAT class
Type ∆σR
mode of fatigue cracking Description of joint
No.
and stress σ considered Steel Al
Longitudinal gusset welded on beam flange, bulb or plate:
ℓ ≤ 50 mm 80 28
50 mm < ℓ ≤ 150 mm 71 25
(t2) 150 mm < ℓ ≤ 300 mm 63 20
ℓ > 300 mm 56 18
C1
For t2 ≤ 0,5 t1, ∆σR may be increased by one class, but
(t1) not over 80 (steel) or 28 (Al); not valid for bulb profiles.
When welding close to edges of plates or profiles (dis-
tance less than 10 mm) and/or the structural element is
subjected to bending, ∆σR is to be decreased by one class.
Gusset with smooth transition (sniped end or radius)
welded on beam flange, bulb or plate;
c ≤ 2 t2, max. 25 mm
r
j

(t2) r ≥ 0,5 h 71 25
t1

r < 0,5 h or ϕ ≤ 20° 63 20

c

C2
ϕ > 20° see joint type C1
For t2 ≤ 0,5 t1, ∆σR may be increased by one class;
h

not valid for bulb profiles.

When welding close to the edges of plates or profiles (dis-
tance less than 10 mm), ∆σR is to be decreased by one class.
Fillet welded non-load-carrying lap joint welded to
longitudinally stressed component.
– flat bar 56 20
– to bulb section 56 20
C3 – to angle section 50 18
For ℓ > 150 mm, ∆σR has to be decreased by one class,
while for ℓ ≤ 50 mm, ∆σR may be increased by one class.
If the component is subjected to bending, ∆σR has to
be reduced by one class.
Fillet welded lap joint with smooth transition (sniped end
r with ϕ ≤ 20° or radius) welded to longitudinally stressed
j

component.
(t) 56 20
c

C4 – flat bar
– to bulb section 56 20
h

– to angle section 50 18
c ≤ 2 t, max. 25 mm
Longitudinal flat side gusset welded on plate or beam
flange edge
ℓ ≤ 50 mm 56 20
50 mm < ℓ ≤ 150 mm 50 18
(t2) 45 16
150 mm < ℓ ≤ 300 mm
C5
ℓ > 300 mm 40 14
(t1)
For t2 ≤ 0,7 t1, ∆σR may be increased by one class, but
not over 56 (steel) or 20 (Al).
If the plate or beam flange is subjected to in-plane
bending, ∆σR has to be decreased by one class.
Chapter 1 Section 20 C Fatigue Strength I - Part 1
Page 20–14 GL 2012

Table 20.3 Catalogue of details (continued)

C. Non-load-carrying attachments

Joint configuration showing FAT class

Type ∆σR
mode of fatigue cracking Description of joint
No.
and stress σ considered
Steel Al

Longitudinal flat side gusset welded on plate edge

or beam flange edge, with smooth transition (sniped
r
j

(t2) end or radius); c ≤ 2 t2, max. 25 mm

r ≥ 0,5 h 50 18
c

C6
r < 0,5 h or ϕ ≤ 20° 45 16
h

(t1) ϕ > 20° see joint type C5

For t2 ≤ 0,7 t1, ∆σR may be increased by one class.

Longitudinal flat side gusset welded on plate edge or

beam flange edge, with smooth transition radius
r
r/h > 1/3 or r ≥ 150 mm 90 36
1/6 < r/h < 1/3 71 28
C6a r/h < 1/6 50 22
h

Smooth transition radius formed by grinding the full

penetration weld area in order to achieve a notch-
free transition area. Final grinding shall be
performed parallel to stress direction.

C7 Transverse stiffener with fillet welds (applicable for 80 28

short and long stiffeners)

C8 Non-load-carrying shear connector 80 28

End of long doubling plate on beam, welded ends

(based on stress range in flange at weld toe)
tD ≤ 0,8 t 56 20
0,8 t < tD ≤ 1,5 t 50 18
tD > 1,5 t 45 16
tD
t

The following features increase ∆σR by one class

C9 accordingly:
– reinforced ends according to Section 19,
Fig. 19.4
– weld toe angle ≤ 30 °
– length of doubling ≤ 300 mm
For length of doubling ≤ 150 mm, ∆σR may be in-
creased by two classes.
I - Part 1 Section 20 C Fatigue Strength Chapter 1
GL 2012 Page 20–15

Table 20.3 Catalogue of details (continued)

D. Cruciform joints and T-joints

Joint configuration showing FAT class

Type ∆σR
mode of fatigue cracking Description of joint
No.
and stress σ considered
Steel Al

Cruciform or tee-joint K-butt welds with full

penetration or with defined incomplete root
D1 penetration according to Section 19, Fig. 19.9.
cruciform joint 71 25
tee-joint 80 28

Cruciform or tee-joint with transverse fillet

welds, toe failure (root failure particularly for
D2 throat thickness a < 0,7 ⋅ t, see joint type D3)
cruciform joint 63 22
tee-joint 71 25

Welded metal in transverse load-carrying fillet

welds at cruciform or tee-joint, root failure
(based on stress range in weld throat), see also
joint type No. D2
D3 a ≥ t/3 36 12
a < t/3 40 14
Note
Crack initiation at weld root

Full penetration weld at the connection between

a hollow section (e.g. pillar) and a plate,
for tubular section 56 20
D4 for rectangular hollow section 50 18
(t)
For t ≤ 8 mm, ∆σR has to be decreased by one
class.

Fillet weld at the connection between a hollow

section (e.g. pillar) and a plate,
for tubular section 45 16
D5 for rectangular hollow section 40 14
(t) The stress is to be related to the weld sectional
area. For t ≤ 8 mm, ∆σR has to be decreased by
one class.

d Continuous butt or fillet weld connecting a pipe

penetrating through a plate
(((((
((
(( (((

71 25
((((

((((((
d ≤ 50 mm
d > 50 mm 63 22
D6

Note
For large diameters an assessment based on
local stress is recommended.
Chapter 1 Section 20 C Fatigue Strength I - Part 1
Page 20–16 GL 2012

Table 20.3 Catalogue of details (continued)

E. Unwelded base material

Joint configuration showing FAT class

Type ∆σR
mode of fatigue cracking Description of joint
No.
and stress σ considered
Steel Al

Rolled or extruded plates and sections as well as 160 71

E1 (m0 = 5) (m0 = 5)
seamless pipes, no surface or rolling defects

Plate edge sheared or machine-cut by any thermal

process with surface free of cracks and notches,
cutting edges chamfered or rounded by means of
smooth grinding, groove direction parallel to the 150
E2a loading direction. ––
(m0 = 4)
Stress increase due to geometry of cut-outs to be
considered by means of direct numerical calcula-
tion of the appertaining maximum notch stress
range.
Plate edge sheared or machine-cut by any thermal
process with surface free of cracks and notches,
140 40
E2 cutting edges broken or rounded.
(m0 = 4) (m0 = 4)
Stress increase due to geometry of cut-outs to be
considered. 1
Plate edge not meeting the requirements of type
E2, but free from cracks and severe notches.

Machine cut or sheared edge: 125 36

(m0 = 3,5) (m0 = 3,5)
E3
Manually thermally cut: 100 32
(m0 = 3,5) (m0 = 3,5)
Stress increase due to geometry of cut-outs to be
considered. 1
1 Stress concentrations caused by an opening to be considered as follows:

∆σmax = Kt ⋅ ∆σΝ
Kt : Notch factor according to Section 3, J.
∆σN : Nominal stress range related to net section

alternatively direct determination of ∆σmax from FE-calculation, especially in case of hatch openings or multiple arrangement of
openings.

Partly based on Recommendations on Fatigue of Welded Components, reproduced from IIW document XIII-2151-07 / XV-1254-07, by kind
permission of the International Institute of Welding.
I - Part 1 Section 20 C Fatigue Strength Chapter 1
GL 2012 Page 20–17

Table 20.4 Various intersections

Stiffener

Longitudinal
Transverse web
Transverse
Side shell plating web
or longitudinal
bulkhead plating
Fracture

1 1

Side shell plating

or longitudinal
Longitudinal bulkhead plating

Joint configuration FAT class

Loads Description of joint DsR
Locations being at risk for cracks steel

None watertight intersection 80 80 80 80

without heel stiffener.

For predominant longitudinal

load only.

Watertight intersection without 71 71 71 71

heel stiffener (without cyclic load
on the transverse member, see
Section 9, B.4.1)
For predominant longitudinal
load only

With heel stiffener

direct £ 150 45 56 56 63
connection > 150 40 50 50 56
2
overlapping £ 150 50 50 45
connection > 150 45 45 40

With heel stiffener and integrated 45 56 56 63

bracket

With heel stiffener and integrated

bracket and with backing bracket
direct connection 50 63 63 71
overlapping connection 56 56 50

With heel stiffener but considering

the load transferred to the stiffener
(see Section 9, B.4.9)
crack initiation at weld toe 80 71 71 71
crack initiation at weld root 40 40 40

Stress increase due to eccentricity

and shape of cut out has to be
observed
1 Additional stresses due to asymmetric sections have to be observed, see Section 3,L.
2 To be increased by one class, when longitudinal loads only
 Joint configuration showing FAT
Structure or Description of structure or Type mode of fatigue cracking class
equipment detail equipment detail No. Description of joint DsR
and stress s considered
Steel
Chapter 1

Table 20.5
Page 20–18

Unstiffened flange to web joint, to be Cruciform or tee-joint K-butt welds with

assessed according to type D1, D2 or full penetration or with defined incomplete
D3, depending on the type of joint. root penetration according to Section 19,
Fg Fig. 19.9.
The stress in the web is calculated using
71
Section 20

the force Fg in the flange as follows: cruciform joint

r
Fg Fg tee-joint 80
C

s= r×t D1
s
Examples of details

Furthermore, the stress in longitudinal

(t) weld direction has to be assessed accor-
ding to type B2 - B4. In case of additional
shear or bending, also the highest prin-
cible stress may become relevant in the
web, see B.1.4.
Fatigue Strength

Joint at stiffened knuckle of a flange, to Cruciform or tee-joint with transverse fillet

sa be assessed according to type D1, D2 welds, toe failure (root failure particuarly
or D3, depending on the type of joint. for throat thickness a < 0,7 × t, see joint
The stress in the stiffener at the knuckle D2 type D3)
can normally be calculated as follows: cruciform joint 63

2a
sa
tee-joint 71
tf

tf
s = sa t 2 sin a
b
Welded metal in transverse load-carrying
tb fillet welds at cruciform or tee-joint, root 36
D3 failure (based on stress range in weld
s throat), see also joint type No. D2

A Holder welded in way of an opening and £ 150 mm 71

arranged parallel to the edge of the
A-A opening. In way of the rounded corner of an
x (t2) opening with the radius r a minimum
distance x from the edge to be kept
not valid for hatch corner (hatched area):
C1 x [mm] = 15 + 0,175 × r [mm]
(t1)
100 mm £ r £ 400 mm
In case of an elliptical rounding the mean
A value ot both semiaxes to be applied
GL 2012
I - Part 1
 FAT
Structure or Description of structure or Type Joint configuration showing class
equipment detail equipment detail No. mode of fatigue cracking Description of joint DsR
and stress s considered
GL 2012
I - Part 1

steel
Table 20.5

tD

t
d tD £ 0,8 t 71
Circular doubler plate with C9 0,8 t < tD £ 1,5 t 63
max. 150 mm diameter.
Section 20

tD > 1,5 t 56
C

d tD £ 0,8 t 71
Drain plugs with full penetration butt weld

tD
0,8 t < tD £ 1,5 t

tD
63

t
d £ 150 mm tD > 1,5 t 56
C9

t
Assesment corresponding to doubling
Examples of details (continued)

For d > 150 mm

plate.
Fatigue Strength

DsR has to be decreased by one class

Drain plugs with partial penetration 0,2 t < tD £ 0,8 t 50

butt weld and a defined root gap

tD

t
0,8 t < tD £ 1,5 t 45
d
d £ 150 mm C9 1,5 t < tD < 2,0 t 40
For v < 0,4 t For d > 150 mm
or v < 0,4 tD

t
tD
DsR has to be decreased by one class

v
Partial penetration butt weld; the stress 36
For v ³ 0,4 t is to be related to the weld throat sectional
and v ³ 0,4 tD A7 area, weld overfill not to be taken into
account

The detail category is also valid for not Transverse stiffener with fillet welds 80
fully circumferential welded holders (applicable for short and long stiffeners)
C7
For stiffeners loaded in bending DsR
to be downgraded by one class
Page 20–19
Chapter 1
I - Part 1 Section 21 B Hull Outfit Chapter 1
GL 2012 Page 21–1

Section 21

Hull Outfit

A. Partition Bulkheads
W = 12 ⋅ ℓ [cm3 ]
1. General
Spaces, which are to be accessible for the service of ℓ = unsupported span of stiffener [m]
the ship, hold spaces and accommodation spaces are to Where the stiffener spacing deviates from 900 mm,
be gastight against each other.
the section modulus is to be corrected in direct propor-

new Section 27, D.1.2 tion.

new B.1.2.3
2. Partition bulkheads between engine and
boiler rooms
3. Moveable grain bulkheads
2.1 General
3.1 General
2.1.1 Boiler rooms generally are to be separated Movable grain bulkheads may consist of moveable
from adjacent engine rooms by bulkheads. tween deck covers or just by moveable bulkheads.

new Section 27, B.5.2.1
new B.2.1
Unless these bulkheads are watertight or tank bulk-
heads according to Section 11 or 12, the scantlings 3.2 Sealing system
according to 2.2 are sufficient.
3.2.1 A detailed drawing of the sealing system is to

new B.1.1 be submitted for approval.
2.1.2 The bilges are to be separated from each
new B.2.2.1
other in such a way that no oil can pass from the boiler
room bilge to the engine room bilge. Bulkhead open- 3.2.2 Sufficient tightness regarding grain leakage is
ings are to have hinged doors. to be ensured.

new Section 27, B.5.2.2
new B.2.2.2

2.1.3 Where a close connection between engine 3.2.3 A GL type approval of a moveable bulkhead
and boiler room is advantageous in respect of supervi- sealing system is acceptable in lieu of ship specific
sion and safety, complete bulkheads may be dispensed examination.
with, provided the conditions given in the GL Rules
for Machinery Installations (I-1-2) are complied with.
new B.2.2.3

new Section 27, B.5.2.3

2.2 Scantlings
B. Ceiling
2.2.1 The thickness of watertight parts of the parti-
tion bulkheads is not to be less than 6,0 mm. The 1. Bottom ceiling
thickness of the remaining parts may be 5 mm.
1.1 Where in the holds of general cargo ships a

new B.1.2.1 tight bottom ceiling is fitted from board to board, the
thickness of a wooden ceiling shall not be less than
2.2.2 Platforms and decks below the boilers are to 60 mm.
be made watertight; they are to be not less than
6,0 mm in thickness, and are to be well supported.
new C.1.1

new B.1.2.2 1.2 On single bottoms ceilings are to be remov-

able for inspection of bottom plating at any time.
2.2.3 Stiffeners spaced 900 mm apart are to be
fitted. The section modulus of the stiffeners is not to
new C.1.2
be less than:
Chapter 1 Section 21 C Hull Outfit I - Part 1
Page 21–2 GL 2012

1.3 Ceilings on double bottoms are to be laid on relative to the window size and round or oval openings
battens not less than 12,5 mm thick providing a clear with an area exceeding 0,16 m2.
space for drainage of water or leakage oil. The ceiling
may be laid directly on the inner bottom plating, if
new D.1.3
embedded in preservation and sealing compound.
1.4 Side scuttles to the following spaces shall be

new C.1.3 fitted with hinged inside deadlights:

1.4 It is recommended to fit double ceilings un- – spaces below freeboard deck
der the hatchways.
– spaces within the first tier of enclosed super-
1.5 The manholes are to be protected by a steel structures
coaming welded around each manhole, fitted with a
cover of wood or steel, or by other suitable means. – first tier deckhouses on the freeboard deck pro-
tecting openings leading below or considered

new C.1.4 buoyant in stability calculations

2. Side ceiling, ceiling at tank bulkheads Deadlights shall be capable of being closed and se-
cured watertight if fitted below the freeboard deck and
weathertight if fitted above.
2.1 In cargo holds of ordinary dry cargo ships,
side ceiling is to be fitted in general. The side ceiling
new D.1.4
may be omitted if agreed by the Owner. The side
ceilings shall extend from the upper turn of bilge 1.5 Side scuttles shall not be fitted in such a
or from tweendeck up to the lower edge of deck beam position that their sills are below a line drawn parallel
brackets. The clear distance between adjacent wooden to the freeboard deck at side and having its lowest
battens shall not exceed 250 – 300 mm. The thickness point 2.5% of the breadth (B), or 500 mm, which-
shall, in general, not be less than 50 mm. everis the greatest distance, above the Summer Load
Line (or Timber Summer Load Line if assigned), see
2.2 Where tanks are intended to carry liquids at Fig. 21.1.
temperatures exceeding 40 °C, their boundaries facing
the cargo hold shall be fitted with a ceiling. At vertical
new D.1.5
walls, sparred ceilings are sufficient except in holds
intended to carry grain. The ceiling may be dispensed 1.6 If the required damage stability calculations
with only with Owners' consent. indicate that the side scuttles would become immersed
at any intermediate stage of flooding or the final equi-
librium waterline, they shall be of the non-opening
type.
C. Side Scuttles, Windows and Skylights
new D.1.6

1.7 Windows shall not be fitted in the following

1. General
locations:
1.1 Side scuttles and windows, together with – below the freeboard deck
their glasses, deadlights and storm covers 1, if fitted, – in the first tier end bulkheads or sides of en-
shall be of an approved design and substantial con- closed superstructures
struction. Non-metallic frames are not acceptable.
– in first tier deckhouses that are considered

new D.1.1 buoyant in the stability calculations

1.2 Side scuttles are defined as being round or
new D.1.7

oval openings with an area not exceeding 0,16 m2.
1.8 Side scuttles and windows at the side shell in
Round or oval openings having areas exceeding 0,16
the second tier shall be provided with hinged inside
m2 shall be treated as windows.
deadlights capable of being closed and secured

new D.1.2 weathertight if the superstructure protects direct ac-
cess to an opening leading below or is considered
1.3 Windows are defined as being rectangular buoyant in the stability calculations.
openings generally, having a radius at each corner
new D.1.8

1.9 Side scuttles and windows in side bulkheads

1 Deadlights are fitted to the inside of windows and side scuttles,
set inboard from the side shell in the second tier which
while storm covers are fitted to the outside of windows, where protect direct access below to spaces listed in 1.4 shall
accessible, and may be hinged or portable. be provided with either hinged inside deadlights or,
I - Part 1 Section 21 C Hull Outfit Chapter 1
GL 2012 Page 21–3

where they are accessible, permanently attached ex-
new D.1.1

ternal storm covers which are capable of being closed
and secured weathertight. 1.12 Fixed or opening skylights shall have a glass

new D.1.9 thickness appropriate to their size and position as
required for side scuttles and windows. Skylight
1.10 Cabin bulkheads and doors in the second tier glasses in any position shall be protected from me-
and above separating side scuttles and windows from chanical damage and, where fitted in position 1 or 2,
a direct access leading below or the second tier con- shall be provided with permanently attached dead-
sidered buoyant in the stability calculations may be lights or storm covers.
accepted in place of deadlights or storm covers fitted
to the side scuttles and windows.
new D.1.12

new D.1.10
1.13 Additional requirements for passenger ves-
1.11 Deckhouses situated on a raised quarter deck sels given in Section 26 have to be observed.
or on the deck of a superstructure of less than standard

new D.1.13
height may be regarded as being in the second tier as
far as the requirements for deadlights are concerned,
provided that the height of the raised quarter deck or 1.14 Additional requirements for oil tankers given
superstructure is equal to or greater than the standard in Section 24 have to be observed.
quarter deck height.
Line drawn parallel to freeboard deck on side
new D.1.4
below which no side scuttles are allowed

Freeboard deck

Summer load waterline 500 mm or 2,5 % of breath (B),

or timber summer load waterline whichever is the greater
if timber freeboards are assignd

Allowed
Not allowed
Fig. 21.1 Arrangement of side scuttles

2. Design Load
3. Frames
2.1 The design load shall be in accordance with
Section 4 and Section 16. 3.1 The design has to be in accordance with ISO
standard 1751, 3903 and 21005 or any other recog-

new D.2.1
nised, equivalent national or international standard.
2.2 For ships with a length Lc equal to or greater
new D.3.1
than 100 m, loads in accordance with ISO 5779 and
5780 standard have to be calculated additionally. The 3.2 Variations from respective standards may
greater value has to be considered up to the third tier. require additional proof of sufficient strength by direct
calculation or tests. This is to be observed for bridge

new D.2.2
windows in exposed areas (e.g. within forward quarter
2.3 Deviations and special cases are subject to of ships length) in each case.
separate approval.
new D.3.2

new D.2.3
4. Glass panes

4.1 Glass panes have to be made of thermally

toughened safety glass (TSG), or laminated safety
Chapter 1 Section 21 D Hull Outfit I - Part 1
Page 21–4 GL 2012

glass made of TSG. The ISO standards 614, 1095 and tight closed superstructures and deckhouses, they are
3254 are to be observed. to be fitted with non-return valves of automatic type,
which can be operated from a position always accessi-

new D.4.1
ble and above the freeboard deck. Means showing
4.2 The glass thickness for windows and side whether the valves are open or closed (positive means
scuttles has to be determined in accordance with the of closing) are to be provided at the control position.
respective ISO standards 1095 and 3254 or any other
covered by new E
equivalent national or international standard, consider-
ing the design loads given in 2. For sizes deviating 1.4 Where the vertical distance from the summer
from the standards, the formulas given in ISO 3903 load waterline to the inboard end of the discharge pipe
may be used. exceeds 0,01 L, the discharge may have two automatic

new D.4.2 non-return valves without positive means of closing,
provided that the inboard valve is always accessible
4.3 Heated glass panes have to be in accordance for examination, i.e., the valve is to be situated above
with ISO 3434. the tropical or subdivision load line.

new D.4.3
covered by new E
4.4 An equivalent thickness (ts) of laminated
1.5 Where the vertical distance mentioned under
toughened safety glass is to be determined from the
1.4 exceeds 0,02 L, a single automatic non-return
following formula:
valve, without positive means of closing may be ac-
cepted. This relaxation is not valid for compartments
t s = t12 + t 22 + .... + t n2 below the freeboard deck of ships, for which a flood-
ing calculation in the damaged condition is required.

new D.4.4

covered by new E
5. Tests
1.6 Scuppers and discharge pipes originating at
Windows and side scuttles have to be tested in accord- any level and penetrating the shell either more than
ance with the respective ISO standards 1751 and 3903. 450 mm below the freeboard deck or less than
Windows in ship safety relevant areas (i.e. wheelhouse 600 mm above the summer load water line are to be
and others as may be defined) and window sizes not provided with a non-return valve at the shell. This
covered by ISO standards are to be tested at four times valve, unless required by 1.3, may be omitted if a
design pressure. heavy gauge discharge pipe is fitted.

For test requirements for passenger ships see Section
covered by new E
26, I.
1.7 Requirements for seawater valves related to

new D.5 operating the power-plant shall be observed, see the
GL Rules for Machinery Installations (I-1-2), Section
11, I.3.
D. Scuppers, Sanitary Discharges and Freeing
covered by new E
Ports
1.8 All valves including the ship side valves
1. Scuppers and sanitary discharges required under 1.2 to 1.7 are to be of steel, bronze or
other approved ductile material. Ordinary cast iron is
1.1 Scuppers sufficient in number and size to not acceptable. Pipe lines are to be of steel or similar
provide effective drainage of water are to be fitted in material (see also the GL Rules for Machinery Instal-
the weather deck and in the freeboard deck within lations (I-1-2), Section 11).
weathertight closed superstructures and deckhouses.
Cargo decks and decks within closed superstructures
covered by new E
are to be drained to the bilge. Scuppers from super- 1.9 Scuppers and sanitary discharges should not
structures and deckhouses which are not closed be fitted above the lowest ballast waterline in way of
weathertight are also to be led outside. lifeboat launching positions or means for preventing

covered by new E any discharge of water into the life boats are to be
provided for. The location of scuppers and sanitary
1.2 Scuppers draining spaces below the summer discharges is also to be taken into account when ar-
load line, are to be connected to pipes, which are led ranging gangways and pilot lifts.
to the bilges and are to be well protected.

covered by new E

covered by new E

1.3 Where scupper pipes are led outside from

spaces below the freeboard deck and from weather-
I - Part 1 Section 21 E Hull Outfit Chapter 1
GL 2012 Page 21–5

2. Freeing ports 2.6 In ships having open superstructures, ade-

quate freeing ports are to be provided which guarantee
2.1 Where bulwarks on exposed portions of free- proper drainage.
board and/or superstructure decks form wells, ample
provision is to be made for rapidly freeing the decks 2.7 Where trunks are taken into account when cal-
of water. culating the freeboard an open rail is to be fitted in way

new E.2.1 of the trunk for at least 50 % of the length of the trunk.

2.2 Except as provided in 2.3 to 2.5 the minimum Table 21.1 Minimum area of freeing ports
freeing port area on each side of the ship for each well on
the freeboard deck of a ship of type "B" is to be deter- Area of freeing ports
mined by the following formulae in cases where the sheer Breadth of hatchway or in relation to the total
in way of the well is standard or greater than standard: trunk in relation to B area of the bulwark
[%] [%] 1
A = 0,7 + 0,035 ℓ [m2 ] for ℓ ≤ 20 m (each side separately)
2
= 0,07 ℓ [m ] for ℓ > 20 m 40 or less 20
75 or more 10
ℓ = length of bulwark [m]
1 The area of freeing ports at intermediate breadths is to be
ℓmax = 0,7 L obtained by linear interpola tion.
The minimum area for each well on superstructure decks
shall be one half of the area obtained by the formulae. As an equivalent, a continuous bulwark can be fitted
with a continuous slot of 33 % of the bulwark area.
If the bulwark is more than 1,2 m in average height the
required area is to be increased by 0,004 m2 per metre 2.8 The lower edges of the freeing ports shall be as
of length of well for each 0,1 m difference in height. near to the deck as practicable. Two thirds of the freeing
port area required shall be provided in the half of the
If the bulwark is less than 0,9 m in average height, the
well nearest to the lowest point of the sheer curve.
required area may be decreased accordingly.

new E.2.11

new E.2.2
2.9 All such openings in the bulwarks shall be
2.3 In ships with no sheer the area calculated
protected by rails or bars spaced approximately 230
according to 2.2 is to be increased by 50 %. Where the
millimetres apart. If shutters are fitted to freeing ports,
sheer is less than the standard the percentage shall be
ample clearance shall be provided to prevent jamming.
obtained by linear interpolation.
Hinges shall have pins or bearings of non-corrodible

new E.2.3 material.

2.4 In ships of type "B with reduced freeboard"
new E.2.12

the freeing port area on the exposed freeboard deck is
2.10 On containerships with continuous longitudi-
to be obtained as follows:
nal hatch coamings, where water may accumulate
– Where a combination of open rail and rigid between the transverse coamings, freeing ports are to
bulwark is fitted, the length of the open rail is to be provided at both sides, with a minimum section
be at least 50 % of the length of the exposed part area Aq of:
of the freeboard deck.
Aq = 0, 07 ⋅ bQ [m 2 ]
– Where a continuous bulwark is fitted, the free-
ing port area is to be 25 % of the total area of
the bulwarks, where the freeboard is reduced by bQ = breadth of transverse box girder [m]
not more than 60 % of the difference between B
new E.2.13
and A tables. Where the freeboard is reduced by
more than 60 % the area is to be not less than
33 % of the total area of the bulwarks.
E. Air Pipes, Overflow Pipes, Sounding Pipes
2.5 Where a ship is fitted with a trunk on the
freeboard deck, which will not be taken into account 1. Each tank is to be fitted with air pipes, over-
when calculating the freeboard, or where continuous flow pipes and sounding pipes. The air pipes are to be
or substantially continuous hatchway side coamings led to above the exposed deck. The arrangement is to
are fitted between detached superstructures the mini- be such as to allow complete filling of the tank. For the
mum area of the freeing port openings is to be deter- arrangement and scantlings of pipes see the GL Rules
mined from Table 21.1. for Machinery Installations (I-1-2), Section 11, R. The

new E.2.8 height from the deck of the point where the sea water
Chapter 1 Section 21 E Hull Outfit I - Part 1
Page 21–6 GL 2012

may have access is to be at least 760 mm on the free- the summer load waterline, whichever is the
board deck and 450 mm on a superstructure deck. lesser

new F.1
new F.5.2

2. Suitable closing appliances are to be provided 5.3 Applied loading for air pipes, ventilator
for air pipes, overflow pipes and sounding pipes, see pipes and their closing devices
also the GL Rules for Machinery Installations (I-1-2),
Section 11, R. Where deck cargo is carried, the clos- 5.3.1 The pressures p [kN/m2] acting on air pipes,
ing appliances are to be readily accessible at all times. ventilator pipes and their closing devices may be cal-
In ships for which flooding calculations are to be culated from:
made, the ends of the air pipes are to be above the
damage waterline in the flooded condition. Where p = 0,5 ⋅ ρ ⋅ V 2 ⋅ Cd ⋅ Cs ⋅ Cp
they immerge at intermediate stages of flooding, these
conditions are to be examined separately. ρ = density of sea water (1,025 t/m3)

new F.2 V = velocity of water over the fore deck
(13,5 m/sec)
3. Closely under the inner bottom or the tank
top, holes are to be cut into floor plates and side gird- Cd = shape coefficient
ers as well as into beams, girders, etc., to give the air = 0,5 for pipes
free access to the air pipes.
= 0,8 for an air pipe or ventilator head of
Besides, all floor plates and side girders are to be
cylindrical form with its axis in the ver-
provided with limbers to permit the water or oil to
tical direction
reach the pump suctions.
= 1,3 for air pipes or ventilator heads

new F.3
Cs = slamming coefficient
4. Sounding pipes are to be extended to directly
= 3,2
above the tank bottom. The shell plating is to be
strengthened by thicker plates or doubling plates under Cp = protection coefficient
the sounding pipes.
= 0,7 for pipes and ventilator heads located

new F.4 immediately behind a breakwater or
forecastle
5. Special strength requirements for fore = 1,0 elsewhere and immediately behind a
deck fittings bulwark
5.1 General
new F.5.3.1
The following strength requirements are to be ob- 5.3.2 Forces acting in the horizontal direction on the
served to resist green sea forces for the items given pipe and its closing device may be calculated from 5.3.1
below, located within the forward quarter length: using the largest projected area of each component.
– air pipes, ventilator pipes and their closing de-
new F.5.3.2
vices
Exempted from these requirements are air pipes, ven- 5.4 Strength requirements for air pipes, venti-
tilator pipes and their closing devices of the cargo lator pipes and their closing devices
venting systems and the inert gas systems of tankers. 5.4.1 Bending moments and stresses in air and ven-

new F.5.1 tilator pipes are to be calculated at critical positions:
– at penetration pieces
5.2 Application
– at weld or flange connections
For ships that are contracted for construction on or
after 1st January 2004 1 on the exposed deck over the – at toes of supporting brackets
forward 0,25 L, applicable to: Bending stresses in the net section are not to exceed
– all ship types of seagoing service of length 80 m 0,8 ⋅ ReH. Irrespective of corrosion protection, a corro-
or more, where the height of the exposed deck in sion addition to the net section of 2,0 mm is then to be
way of the item is less than 0,1 L or 22 m above applied.

new F.5.4.1
1 For ships contracted for construction prior to 1st January 2004 5.4.2 For standard air pipes of 760 mm height
refer to IACS UR S27 para 2.2. closed by heads of not more than the tabulated pro-
I - Part 1 Section 21 E Hull Outfit Chapter 1
GL 2012 Page 21–7

jected area, pipe thicknesses and bracket heights are specified in Table 21.3. Brackets, where required are
specified in Table 21.2. Where brackets are required, to be as specified in 5.4.2.
three or more radial brackets are to be fitted.

new F.5.4.4
Brackets are to be of gross thickness 8 mm or more, of
minimum length 100 mm, and height according to Ta- 5.4.5 For ventilators of height greater than
ble 21.2 but need not extend over the joint flange for 900 mm, brackets or alternative means of support are
the head. Bracket toes at the deck are to be suitably to be specially considered. Pipe thickness is not to be
supported. taken less than as indicated in the GL Rules for Ma-

new F.5.4.2 chinery Installations (I-1-2), Section 11, Table 11.20a
and 11.20b.
5.4.3 For other configurations, loads, according to

new F.5.4.5
5.3 are to be applied, and means of support determined
in order to comply with the requirements of 5.4.1.
Brackets, where fitted, are to be of suitable thickness 5.4.6 All component part and connections of the air
and length according to their height. Pipe thickness is pipe or ventilator are to be capable of withstanding the
not to be taken less than as indicated in the GL Rules loads defined in 5.3.
for Machinery Installations (I-1-2), Section 11, Table
new F.5.4.6
11.20a and 11.20b.

new F.5.4.3 5.4.7 Rotating type mushroom ventilator heads are
unsuitable for application in the areas defined in 5.2.
5.4.4 For standard ventilators of 900 mm height
new F.5.4.7
closed by heads of not more than the tabulated pro-
jected area, pipe thicknesses and bracket heights are

Table 21.2 760 mm air pipe thickness and bracket standards

Minimum fitted 1 Maximum projected area Height 2

Nominal pipe diameter
gross thickness of head of brackets
[mm]
[mm] [cm2] [mm]
65A 6,0 –– 480
80A 6,3 –– 460
100A 7,0 –– 380
125A 7,8 –– 300
150A 8,5 –– 300
175A 8,5 –– 300
200A 8,5 3 1900 300 3
250A 8,5 3 2500 300 3
300A 8,5 3 3200 300 3
350A 8,5 3 3800 300 3
400A 8,5 3 4500 300 3
1 See IACS Unified Interpretation LL 36 c.
2 Brackets see 5.4.1.3 need not extend over the joint flange for the head.
3 Brackets are required where the as fitted (gross) thickness is less than 10,5 mm, or where the tabulated projected head area is exceeded.

Note:
For other air pipe heights, the relevant requirements of 5.4 are to be applied.
Chapter 1 Section 21 F Hull Outfit I - Part 1
Page 21–8 GL 2012

Table 21.3 900 mm ventilator pipe thickness and bracket standards

Minimum fitted Maximum projected area Height

Nominal pipe diameter
gross thickness of head of brackets
[mm]
[mm] [cm2] [mm]

80A 6,3 –– 460

100A 7,0 –– 380
150A 8,5 –– 300
200A 8,5 550 ––
250A 8,5 880 ––
300A 8,5 1200 ––
350A 8,5 2000 ––
400A 8,5 2700 ––
450A 8,5 3300 ––
500A 8,5 4000 ––

Note:
For other ventilator heights, the relevant requirements of 5.4 are to be applied.

F. Ventilators
1.6 The wall thickness of ventilator posts of a
1. General clear sectional area exceeding 1600 cm2 is to be in-
creased according to the expected loads.
1.1 The height of the ventilator coamings on the
exposed freeboard deck, quarter deck and on exposed
covered by new G.1
superstructure decks in the range 0,25 L from F.P. is
to be at least 900 mm. 1.7 Generally, the coamings and posts shall pass
through the deck and shall be welded to the deck plat-

covered by new G.1 ing from above and below.
1.2 On exposed superstructure decks abaft 0,25 L Where coamings or posts are welded onto the deck
from F.P. the coaming height is not to be less than plating, fillet welds of a = 0,5 ⋅ t0, subject to Section
760 mm. 19, B.3.3 should be adopted for welding inside and
outside.

covered by new G.1

covered by new G.1
1.3 Ventilators of cargo holds are not to have any
connection with other spaces.
1.8 Coamings and posts particularly exposed to

covered by new G.1 wash of sea are to be efficiently connected with the
ship's structure.
1.4 The thickness of the coaming plates is to be
7,5 mm where the clear opening sectional area of the
covered by new G.1
ventilator coamings is 300 cm² or less, and 10 mm
where the clear opening sectional area exceeds 1.9 Coamings of a height exceeding 900 mm are
1600 cm². Intermediate values are to be determined by to be specially strengthened.
direct interpolation. A thickness of 6 mm will gener-
ally be sufficient within not permanently closed super-
covered by new G.1
structures.

covered by new G.1 1.10 Where the thickness of the deck plating is
less than 10 mm, a doubling plate or insert plate of 10
1.5 The thickness of ventilator posts should be at mm thickness is to be fitted. Their side lengths are to
least equal to the thickness of coaming as per 1.4. be equal to twice the length or breadth of the coaming.

covered by new G.1
covered by new G.1
I - Part 1 Section 21 G Hull Outfit Chapter 1
GL 2012 Page 21–9

1.11 Where beams are pierced by ventilator coam- 1.3 For transmitting the forces from the container
ings, carlings of adequate scantlings are to be fitted stowing and lashing equipment into the ship's hull
between the beams in order to maintain the strength of adequate welding connections and local reinforce-
the deck. ments of structural members are to be provided (see
also 2. and 3.).

covered by new G.1

new H.1.3
2. Closing appliances
1.4 The hatchway coamings are to be strength-
2.1 Inlet and exhaust openings of ventilation sys- ened in way of the connections of transverse and lon-
tems are to be provided with easily accessible closing gitudinal struts of cell guide systems.
appliances, which can be closed weathertight against The cell guide systems are not permitted to be con-
wash of the sea. In ships of not more than 100 m in nected to projecting deck plating edges in way of the
length, the closing appliances are to be permanently hatchways. Any flame cutting or welding should be
attached. In ships exceeding 100 m in length, they may avoided, particularly at the deck roundings in the
be conveniently stowed near the openings to which hatchway corners.
they belong.

new H.1.4

new G.2.1
1.5 Where inner bottom, decks, or hatch covers
2.2 For ventilator posts which exceed 4,5 m in are loaded with containers, adequate substructures,
height above the freeboard deck or raised quarterdeck e.g. carlings, half height girders etc., are to be pro-
and above exposed superstructure decks forward of vided and the plate thickness is to be increased where
0,25 L from F.P. and for ventilator posts exceeding required. For welded-in parts, see Section 19, B.2.
2,3 m in height above exposed superstructure decks
abaft 0,25 L from F.P. closing appliances are required
new H.1.5
in special cases only.

new G.2.2 2. Load assumptions

2.1 The scantlings of the local ship structures and

2.3 For the case of fire draught-tight fire dampers
of the container substructures are to be determined on
are to be fitted.
the basis of the Container Stowage and Lashing Plan.

new G.2.3

new H.2.1

3. For special strength requirements for fore 2.2 For determining scantlings the following
deck fittings, see Section 21, E.5. design forces are to be used which are assumed to act

new G.2.6 simultaneously in the centre of gravity of a stack:
ship's transverse (y-)direction:
0,5 g ⋅ G [kN]
G. Stowage of Containers
ship's vertical (z-)direction:
1. General (1 + av ) g ⋅ G [kN]

1.1 All parts for container stowing and lashing G = stack mass [t]
equipment are to comply with the GL Rules for Stow-
av = see Section 4, C.1.1
age and Lashing of Containers (I-1-20). All parts
which are intended to be welded to the ship's hull or
new H.2.2
hatch covers are to be made of materials complying
with and tested in accordance with the Rules II –
Materials and Welding. 3. Permissible stresses

new H.1.1 3.1 For hatchway covers in pos. 1 and 2 loaded

with containers, the permissible stresses according to
1.2 All equipment on deck and in the holds es- Section 17, B.2. are to be observed.
sential for maintaining the safety of the ship and
which are to be accessible at sea, e.g. fire fighting
new H.3.1
equipment, sounding pipes etc., should not be made
inaccessible by containers or their stowing and lashing 3.2 The stresses in local ship structures and in
equipment. substructures for containers as well as for cell guide
systems and lashing devices in the hatch covers of

new H.1.2 cargo decks are not to exceed the following values:
Chapter 1 Section 21 J Hull Outfit I - Part 1
Page 21–10 GL 2012

R eH – connection of the car decks to the hull structure

σb =
1,5 – moving and lifting gear of the car decks

new J.1.2
R eH
τ =
2,3 1.3 Car decks in accordance with these require-
ments may be made of hull structural steel or of the
R eH following materials:
σv = σ2b + 3τ2 =
1,3 – structural steel R St 37-2 (Fe 360 B) and
St 52-3 (Fe 510 D1)

new H.3.2
– seawater resisting aluminium alloys
3.3 For dimensioning the double bottom in case
new J.1.3
of single point loads due to 20'- or 40'-containers, see
Section 8, B.8.2.
2. Design loads

new H.3.3
2.1 For determining the deck scantlings, the
3.4 Where other structural members of the hull, following loads are to be used:
e.g. frames, deck beams, bulkheads, hatchway coam-
ings, bulwark stays etc. are subjected to loads from – uniformly distributed load resulting from the
containers, cell guide systems and container lashing mass of the deck and maximum number of cars
devices, these members are to be strengthened wher- to be carried. This load is not to be taken less
ever necessary so that the actual stresses will not ex- than 2,5 kN/m2.
ceed those upon which the formulae in the respective – wheel load P
Sections are based.
Where all wheels of one axle are standing on a

new H.3.4
deck girder or a deck beam, the axle load is to
be evenly distributed on all wheels.
Where not all of the wheels of one axle are
H. Lashing Arrangements standing on a deck girder or a deck beam, the
following wheel loads are to be used:
Lashing eyes and holes are to be arranged in such a
way as to not unduly weaken the structural members P = 0,5 × axle load for 2 wheels per axle
of the hull. In particular where lashings are attached to P = 0,3 × axle load for 4 wheels per axle
frames, they are to be so arranged that the bending
moment in the frames is not unduly increased. Where P = 0,2 × axle load for 6 wheels per axle
necessary, the frame is to be strengthened.

new J.2.1

new I
2.2 For determining the scantlings of the suspen-
sions, the increased wheel load in case of four and six
J. Car Decks wheels per axle as per 2.1 need not be considered.

new J.2.2
1. General
3. Plating
1.1 These Rules apply to movable as well as to
removable car decks not forming part of the ship's 3.1 The thickness of the plating is to be deter-
structure. mined according to the formulae as per Section 7, B.2.
Where aluminium alloy is used, the thickness is to be

new J.1.1 determined as per Section 2, D.1.
new J.3.1
1.2 The following information should be in- 3.2 The thickness of plywood is to be determined
cluded in the plans to be submitted for approval: taking into account a safety factor of 6 against the
– scantlings of the car decks minimum ultimate strength of the material.
– masses of the car decks Where plywood plates, supported on two sides only,
are subjected to single loads, 1,45 times the unsup-
– number and masses of cars intended to be ported span may be taken as effective width of the
stowed on the decks plating.
– wheel loads and distance of wheels
new J.3.2
I - Part 1 Section 21 L Hull Outfit Chapter 1
GL 2012 Page 21–11

4. Permissible stresses K. Life Saving Appliances

4.1 In steel stiffeners and girders as well as in the 1. It is assumed that for the arrangement and
steel structural elements of the suspensions, subjected operation of lifeboats and other life-saving appliances
to loads as per 2. including the acceleration factor av the regulations of SOLAS 74 or those of the compe-
according to Section 4, C.1.1 the following permissi- tent Authority are complied with.
ble stresses are to be observed:

new K.1
Normal and bending stresses (tension and compres-
sion): 2. The design appraisal and testing of life boats
with their launching appliances and of other life sav-
140
σ ≤ [N / mm 2 ] ing appliances are not part of Classification.
k
However, approval of the hull structure in way of the
Shear stresses: launching appliances taking into account the forces
from the above appliances is part of classification.
90
τ ≤ [N / mm 2 ]
new K.2
k

Combined stresses: Note

For ships subject to the requirements of See-Berufs-
2 2 180 genossenschaft and for ships for which GL has been
σv = σ + 3τ ≤ [N / mm 2 ]
k authorized by the competent Administration to issue
the safety construction - or safety equipment certifi-
k = material factor according to Section 2, B.2. cates - as well as in all cases where GL has been re-
quested to approve the launching appliances, the GL
= 0,72 for Fe 510 D1 (St 52-3)
Guidelines for Life-Saving Launching Appliances (VI-
= 1,0 for Fe 360 B (R St 37-2) 2-1) apply.

new J.4.1
new K.2 Note

4.2 Where aluminium alloys are used, the per-

missible stresses may be derived from multiplying the
L. Signal and Radar Masts
permissible stresses specified for ordinary hull struc-
tural steel by the factor 1/kAℓ (kAℓ = material factor
for aluminium according to Section 2, D.1.). 1. General

new J.4.2 1.1 Drawings of masts, mast substructures and

hull connections are to be submitted for approval.
5. Permissible deflection
new L.1.1

5.1 The deflection of girders subjected to loads 1.2 Loose component parts are to comply with
stipulated under 2. is not to exceed: the GL Guidelines for the Construction and Survey of
Lifting Appliances (VI-2-2). They are to be tested and
ℓ certified by GL.
f =
200

new L.1.2
ℓ = unsupported span of girder
1.3 Other masts than covered by 2. and 3. as well

new J.5.1 as special designs, shall as regards dimensions and
construction in each case be individually agreed with
GL.
5.2 An adequate safety distance should be main-
tained between the girders of a loaded deck and the
new L.1.3
top of cars towed on the deck below.

new J.5.2 2. Single tubular masts
The following requirements apply to tubular or
6. Buckling equivalent rectangular sections made of steel with an
ultimate tensile strength of 400 N/mm2, which are
The buckling strength of girders is to be proved ac- designed to carry only signals (navigation lanterns,
cording to Section 3, F., if required. flag and day signals).

new Section 3, D.1
Chapter 1 Section 21 L Hull Outfit I - Part 1
Page 21–12 GL 2012

new L.2 a = the distance of the hauling points of the

shrouds from the transverse section through
2.1 Stayed masts the hound
b = the distance of the hauling points of the
2.1.1 Stayed masts may be constructed as simply shrouds from the longitudinal section through
supported masts (rocker masts) or may be supported the hound
by one or more decks (constrained masts).
Alternative arrangements of stayings are to be of

new L.2.1.1 equivalent stiffness.

new L.2.1.6
2.1.2 The diameter of stayed steel masts in the
uppermost housing is to be at least 20 mm for each 2.2 Unstayed masts
1 m length of hounding. The length of the mast top
above the hound is not to exceed ℓw /3 (ℓw denotes the 2.2.1 Unstayed masts may be completely con-
hounding [m]). strained in the uppermost deck or be supported by two
or more decks. (In general, the fastenings of masts to

new L.2.1.2 the hull of a ship should extend over at least one deck
height.)
2.1.3 Masts according to 2.1.2 may be gradually
tapered towards the hound to 75 per cent of the diame-
new L.2.2.1
ter at the uppermost housing. The plate thickness is
not to be less than 1/70 of the diameter or at least 2.2.2 The scantlings for unstayed steel masts are
4 mm, see 4.1. given in the Table 21.5.

new L.2.2.2

new L.2.1.3

2.1.4 Wire ropes for shrouds are to be thickly gal- Table 21.5 Dimensions of unstayed steel masts
vanized. It is recommended to use wire ropes com-
posed of a minimum number of thick wires, as for Length of
instance a rope construction 6 × 7 with a tensile break- mast ℓm 6 8 10 12 14
ing strength of 1570 N/mm2. [m]

new L.2.1.4 D × t [mm] 160 × 4 220 × 4 290 × 4,5 360 × 5,5 430 × 6,5

2.1.5 Where masts are stayed forward and aft by ℓm = length of mast from uppermost support to the
one shroud on each side of the ship, steel wire ropes top
are to be used with a tensile breaking strength of D = diameter of mast at uppermost support
1570 N/mm2 according to Table 21.4. t = plate thickness of mast

new L.2.1.5
2.2.3 The diameter of masts may be gradually
tapered to D/2 at the height of 0,75 ℓm.
Table 21.4 Ropes and shackles of stayed steel
masts
new L.2.2.3

h [m] 6 8 10 12 14 16 3. Box girder and frame work masts

Rope diameter 3.1 For dimensioning the dead loads, acceleration

14 16 18 20 22 24 forces and wind loads are to be considered.
[mm]

new L.3.1
Nominal size of
shackle, rigging 2,5 3 4 5 6 8
screw, rope socket 3.2 Where necessary, additional loads e. g. loads
caused by the sea fastening of crane booms or tension
h = height of hound above the hauling of the shrouds. wires are also to be considered.

new L.3.2
2.1.6 Where steel wire ropes according to Table 3.3 The design loads for 3.1 and 3.2 as well as
21.4 are used, the following conditions apply: the allowable stresses can be taken from the GL Guide-
lines for the Construction and Survey of Lifting Ap-
b ≥ 0,3 h pliances (VI-2-2).
0,15 h ≤ a ≤ b
new L.3.3
I - Part 1 Section 21 N Hull Outfit Chapter 1
GL 2012 Page 21–13

3.4 Single tubular masts mounted on the top may 4.9 If possible from the construction point of
be dimensioned according to 2. view, ladders should be at least 0,30 m wide.

new L.3.4 The distance between the rungs shall be 0,30 m. The
horizontal distance of the rung centre from fixed parts
3.5 In case of thin walled box girder masts stiff- shall not be less than 0,15 m. The rungs shall be
eners and additional buckling stiffeners may be neces- aligned and be made of square steel bars 20/20 edge
sary. up.

new L.3.5
new L.4.9

4.10 Platforms on masts which have to be used for

4. Structural details operational reasons, shall have a rail of at least 0,90 m
in height with one intermediate bar. Safe access from
4.1 Steel masts closed all-round shall have a wall the mast ladders to the platform is to be provided.
thickness of at least 4 mm.

new L.4.10
For masts not closed all-round the minimum wall
thickness is 6 mm. 4.11 On masts additional devices have to be in-
For masts used as funnels a corrosion addition of at stalled consisting of foot, back, and hand rings ena-
least 1 mm is required. bling safe work in places of servicing and mainte-
nance.

new L.4.1

new L.4.11
4.2 The ship's side foundations are to be dimen-
sioned in accordance with the acting forces.

new L.4.2
M. Loading and Lifting Gear
4.3 Doubling plates at mast feet are permissible
only for the transmission of compressive forces since 1. The design appraisal and testing of loading
they are generally not suitable for the transmission of and lifting gear on ships are not part of classification.
tensile forces or bending moments. However, approval of the hull structure in way of

new L.4.3 loading and lifting gear taking into account the forces
from the gear is part of classification.
4.4 In case of tubular constructions all welded
new M
fastenings and connections shall be of full penetration
weld type. Note

new L.4.4 For ships subject to the requirements of See-Berufs-
genossenschaft, the GL Guidelines for the Construc-
4.5 If necessary, slim tubes are to be additionally tion and Survey of Lifting Appliances (VI-2-2) apply.
supported in order to avoid vibrations.
These Guidelines will be applied in all cases where

new L.4.5 GL is entrusted with the judgement of loading and
lifting gears of ships.
4.6 The dimensioning normally does not require
new M Note
a calculation of vibrations. However, in case of undue
vibrations occurring during the ship's trial a respective
calculation will be required.

new L.4.6 N. Access to the Cargo Area of Oil Tankers
and Bulk Carriers
4.7 For determining scantlings of masts made Special measures are to be taken for safe access to and
from aluminium or austenitic steel, the requirements working in spaces in and forward of the cargo area of
given in Section 2, D. and E. apply. tankers and bulk carriers for the purpose of mainte-
nance and carrying out surveys.

new L.4.7

new Section 27, D.5
4.8 At masts solid steel ladders have to be fixed
at least up to 1,50 m below top, if they have to be Note
climbed for operational purposes. Above them, suit-
able handgrips are necessary. This requirement is considered to be complied with
where SOLAS, Chapter II-1, Reg. 3-6, is adhered to.

new L.4.8 Abstract of this Regulation:
Chapter 1 Section 21 N Hull Outfit I - Part 1
Page 21–14 GL 2012

1. Safe access to cargo holds, cargo tanks, 2.3 Flight of an inclined ladder
ballast tanks and other spaces
Flight of an inclined ladder means the actual stringer
length of an inclined ladder. For vertical ladders, it is
1.1 Safe access to cargo holds, cofferdams, bal- the distance between the platforms.
last tanks, cargo tanks and other spaces in the cargo
area shall be direct from the open deck and such as to
new Section 27, D.5.1
ensure their complete inspection. Safe access to dou-
ble bottom spaces may be from a pump-room, deep 2.4 Stringer
cofferdam, pipe tunnel, cargo hold, double hull space
or similar compartment not intended for the carriage Stringer means:
of oil or hazardous cargoes. – the frame of a ladder; or

new Section 27, D.5.3.1 – the stiffened horizontal plating structure fitted
on the side shell, transverse bulkheads and/or
1.2 Tanks, and subdivisions of tanks, having a longitudinal bulkheads in the space. For the
length of 35 m or more, shall be fitted with at least purpose of ballast tanks of less than 5 m width
two access hatchways and ladders, as far apart as forming double side spaces, the horizontal plat-
practicable. Tanks less than 35 m in length shall be ing structure is credited as a stringer and a lon-
served by at least one access hatchway and ladder. gitudinal permanent means of access, if it pro-
When a tank is subdivided by one or more swash vides a continuous passage of 600 mm or more
bulkheads or similar obstructions which do not allow in width past frames or stiffeners on the side
ready means of access to the other parts of the tank, at shell or longitudinal bulkhead. Openings in
least two hatchways and ladders shall be fitted. stringer plating utilized as permanent means of
access shall be arranged with guard rails or

new Section 27, D.5.3.2 grid covers to provide safe passage on the
stringer or safe access to each transverse web.
1.3 Each cargo hold shall be provided with at

new Section 27, D.5.1
least two means of access as far apart as practicable.
In general, these accesses should be arranged diago-
nally, for example one access near the forward bulk- 2.5 Vertical ladder
head on the port side, the other one near the aft bulk- Vertical ladder means a ladder of which the inclined
head on the starboard side. angle is 70º and over up to 90º. A vertical ladder shall
not be skewed by more than 2º.

new Section 27, D.5.3.3

new Section 27, D.5.1
1.4 Where a permanent means of access may be
susceptible to damage during normal cargo loading 2.6 Overhead obstructions
and unloading operations or where it is impracticable
Overhead obstructions mean the deck or stringer
to fit permanent means of access, the Administration
structure including stiffeners above the means of ac-
may allow, in lieu thereof, the provision of movable or
cess.
portable means of access, as specified in the Technical
provisions, provided that the means of attaching,
new Section 27, D.5.1
rigging, suspending or supporting the portable means
of access forms a permanent part of the ship's struc- 2.7 Distance below deck head
ture. All portable equipment shall be capable of being
readily erected or deployed by ship's personnel. Distance below deck head means the distance below
the plating.

new Section 27, D.5.2

new Section 27, D.5.1
2. Definitions 2.8 Cross deck
2.1 Rung Cross deck means the transverse area of the main
deck which is located inboard and between hatch
Rung means the step of a vertical ladder or step on the coamings.
vertical surface.

new Section 27, D.5.1

new Section 27, D.5.1
3. Technical provisions
2.2 Tread
Tread means the step of an inclined ladder or step for 3.1 Structural members subject to the close-up
the vertical access opening. inspections and thickness measurements of the ship's
structure, except those in double bottom spaces, shall

new Section 27, D.5.1 be provided with a permanent means of access to the
I - Part 1 Section 21 N Hull Outfit Chapter 1
GL 2012 Page 21–15

extent as specified in Table 21.6 and Table 21.7, as equally spaced at a distance apart, measured verti-
applicable. For oil tankers and wing ballast tanks of cally, of between 200 mm and 300 mm. When steel is
ore carriers, approved alternative methods may be used, the treads shall be formed of two square bars of
used in combination with the fitted permanent means not less than 22 mm by 22 mm in section, fitted to
of access, provided that the structure allows for its form a horizontal step with the edges pointing up-
safe and effective use. ward. The treads shall be carried through the side
stringers and attached thereto by double continuous

new Section 27, D.5.5.1 welding. All inclined ladders shall be provided with
handrails of substantial construction on both sides,
3.2 Permanent means of access should as far as fitted at a convenient distance above the treads.
possible be integral to the structure of the ships, thus
ensuring that they are robust and at the same time
new Section 27, D.5.5.6
contributing to the overall strength of the structure of
the ship. 3.7 For vertical ladders or spiral ladders, the
width and construction should be in accordance with

new Section 27, D.5.5.2 international or national standards accepted by the
Administration.
3.3 Elevated passageways forming sections of a
permanent means of access, where fitted, shall have a
new Section 27, D.5.5.7
minimum clear width of 600 mm, except for going
around vertical webs where the minimum clear width 3.8 No free-standing portable ladder shall be
may be reduced to 450 mm, and have guard rails over more than 5 m long.
the open side of their entire length. Sloping structures
providing part of the access shall be of a non-skid
new Section 27, D.5.5.8
construction. Guard rails shall be 1,000 mm in height
and consist of a rail and an intermediate bar 500 mm 3.9 Alternative means of access include, but are
in height and of substantial construction. Stanchions not limited to, such devices as:
shall be not more than 3 m apart – hydraulic arm fitted with a stable base

new Section 27, D.5.5.3 – wire lift platform

3.4 Access to permanent means of access and – staging

vertical openings from the ship's bottom shall be pro- – rafting
vided by means of easily accessible passageways,
ladders or treads. Treads shall be provided with lat- – root arm or remotely operated vehicle (ROV)
eral support for the foot. Where the rungs of ladders
– portable ladders more than 5 m long shall only
are fitted against a vertical surface, the distance from
be utilized if fitted with a mechanical device to
the centre of the rungs to the surface shall be at least
secure the upper end of the ladder
150 mm. Where vertical manholes are fitted higher
than 600 mm above the walking level, access shall be – other means of access, approved by and accept-
facilitated by means of treads and hand grips with able to the Administration
platform landings on both sides.
Means for safe operation and rigging of such equip-

new Section 27, D.5.5.4 ment to and from and within the spaces shall be
clearly described in the Ship Structure Access Man-
3.5 Permanent inclined ladders shall be inclined ual.
at an angle of less than 70º. There shall be no obstruc-
tions within 750 mm of the face of the inclined ladder,
new Section 27, D.5.5.9
except that in way of an opening this clearance may
be reduced to 600 mm. Resting platforms of adequate 3.10 For access through horizontal openings,
dimensions shall be provided, normally at a maximum hatches or manholes, the minimum clear opening shall
of 6 m vertical height. Ladders and handrails shall be not be less than 600 mm × 600 mm. When access to a
constructed of steel or equivalent material of adequate cargo hold is arranged through the cargo hatch, the
strength and stiffness and securely attached to the top of the ladder shall be placed as close as possible
structure by stays. The method of support and length to the hatch coaming. Access hatch coamings having a
of stay shall be such that vibration is reduced to a height greater than 900 mm shall also have steps on
practical minimum. In cargo holds, ladders shall be the outside in conjunction with the ladder.
designed and arranged so that cargo handling diffi-
new Section 27, D.5.5.10
culties are not increased and the risk of damage from
cargo handling gear is minimized.
3.11 For access through vertical openings, or

new Section 27, D.5.5.4 manholes, in swash bulkheads, floors, girders and web
frames providing passage through the length and
3.6 The width of inclined ladders between string- breadth of the space, the minimum opening shall be
ers shall not be less than 400 mm. The treads shall be not less than 600 mm × 800 mm at a height of not
Chapter 1 Section 21 N Hull Outfit I - Part 1
Page 21–16 GL 2012

more than 600 mm from the passage unless gratings ings referred to in 3.10 and 3.11, if the ability to trav-
or other foot holds are provided. erse such openings or to remove an injured person
can be proved to the satisfaction of the Administra-

new Section 27, D.4.4.11 tion.
3.12 For oil tankers of less than 5,000 tonnes
deadweight, the Administration may approve, in spe-
cial circumstances, smaller dimensions for the open-
new Section 27, D.5.5.12

Table 21.6 Means of access for ballast and cargo tanks of oil tankers

Water ballast wing tanks of less than 5 m width

Water ballast tanks except those specified
forming double side spaces and
in the right column, and cargo oil tanks
their bilge hopper sections

Access to the underdeck and vertical structure

For tanks of which the height is 6 m and over con- For double side spaces above the upper knuckle
taining internal structures, permanent means of ac- point of the bilge hopper sections, permanent means
cess shall be provided in accordance with 1. to 6.: of access are to be provided in accordance with 1. to
3.:
1. continuous athwartship permanent access ar- 1. where the vertical distance between horizontal
ranged at each transverse bulkhead on the stiff- uppermost stringer and deck head is 6 m or
ened surface, at a minimum of 1,6 m to a maxi- more, one continuous longitudinal permanent
mum of 3 m below the deck head; means of access shall be provided for the full
length of the tank with a means to allow passing
2. at least one continuous longitudinal permanent through transverse webs installed at a minimum
means of access at each side of the tank. One of of 1,6 m to a maximum of 3 m below the deck
these accesses shall be at a minimum of 1,6 m to head with a vertical access ladder at each end of
a maximum of 6 m below the deck head and the the tank;
other shall be at a minimum of 1,6 m to a maxi-
mum of 3 m below the deck head; 2. continuous longitudinal permanent means of ac-
cess, which are integrated in the structure, at a
3. access between the arrangements specified in vertical distance not exceeding 6 m apart; and
1. and 2. and from the main deck to either 1. or
2.; 3. plated stringers shall, as far as possible, be in
alignment with horizontal girders of transverse
4. continuous longitudinal permanent means of bulkheads.
access which are integrated in the structural
member on the stiffened surface of a longitudi-
nal bulkhead, in alignment, where possible, with
horizontal girders of transverse bulkheads are
to be provided for access to the transverse webs
unless permanent fittings are installed at the
uppermost platform for use of alternative
means, as defined in 3.9 for inspection at inter-
mediate heights;
5. for ships having cross-ties which are 6 m or
more above tank bottom, a transverse perma-
nent means of access on the cross-ties providing
inspection of the tie flaring brackets at both
sides of the tank, with access from one of the
longitudinal permanent means of access in 4.;
and
6. alternative means as defined in 3.9 may be pro-
vided for small ships as an alternative to 4. for
cargo oil tanks of which the height is less than
17 m.
I - Part 1 Section 21 N Hull Outfit Chapter 1
GL 2012 Page 21–17

Table 21.6 Means of access for ballast and cargo tanks of oil tankers (continued)

Water ballast wing tanks of less than 5 m width

Water ballast tanks except those specified
forming double side spaces and
in the right column, and cargo oil tanks
their bilge hopper sections

Access to the underdeck and vertical structure

For tanks of which the height is less than 6 m, For bilge hopper sections of which the vertical dis-
alternative means as defined in 3.9 or portable tance from the tank bottom to the upper knuckle point
means may be utilized in lieu of the permanent is 6 m and over, one longitudinal permanent means
means of access. of access shall be provided for the full length of the
tank. It shall be accessible by vertical permanent
means of access at each end of the tank.
Where the vertical distance is less than 6 m, alterna-
tive means as defined in 3.9 or portable means of
access may be utilised in lieu of the permanent
means of access. To facilitate the operation of the
alternative means of access, in-line openings in hori-
zontal stringers shall be provided. The openings
shall be of an adequate diameter and shall have suit-
able protective railings.
The longitudinal continuous permanent means of ac-
cess may be installed at a minimum 1,6 m to maxi-
mum 3 m from the top of the bilge hopper section. In
this case, a platform extending the longitudinal con-
tinuous permanent means of access in way of the
webframe may be used to access the identified struc-
tural critical areas.
Alternatively, the continuous longitudinal permanent
means of access may be installed at a minimum of
1,2 m below the top of the clear opening of the web
ring allowing a use of portable means of access to
reach identified structural critical areas.

Fore peak tanks

For fore peak tanks with a depth of 6 m or more at
the centre line of the collision bulkhead, a suitable
means of access shall be provided for access to criti-
cal areas such as the underdeck structure, stringers,
collision bulkhead and side shell structure.

Stringers of less than 6 m in vertical distance from

the deck head or a stringer immediately above are
considered to provide suitable access in combination
with portable means of access.
In case the vertical distance between the deck head
and stringers, stringers or the lowest stringer and
the tank bottom is 6 m or more, alternative means of
access as defined in 3.9 shall be provided.
Chapter 1 Section 21 N Hull Outfit I - Part 1
Page 21–18 GL 2012

Table 21.7 Means of access for bulk carriers

Cargo holds Ballast tanks

Access to underdeck structure Top side tanks

Permanent means of access shall be fitted to provide For each topside tank of which the height is 6 m and
access to the overhead structure at both sides of the over, one longitudinal continuous permanent means
cross deck and in the vicinity of the centreline. Each of access shall be provided along the side shell webs
means of access shall be accessible from the cargo and installed at a minimum of 1,6 m to a maximum of
hold access or directly from the main deck and in- 3 m below deck with a vertical access ladder in the
stalled at a minimum of 1,6 m to a maximum of 3 m vicinity of each access to that tank.
below the deck. An athwartship permanent means of
access fitted on the transverse bulkhead at a mini- If no access holes are provided through the trans-
mum 1,6 m to a maximum 3 m below the cross-deck verse webs within 600 mm of the tank base and the
head is accepted as equivalent. web frame rings have a web height greater than 1 m
in way of side shell and sloping plating, then step
Access to the permanent means of access to over- rungs/grab rails shall be provided to allow safe ac-
head structure of the cross deck may also be via the cess over each transverse web frame ring.
upper stool.
Three permanent means of access, fitted at the end
Ships having transverse bulkheads with full upper bay and middle bay of each tank, shall be provided
stools with access from the main deck which allows spanning from tank base up to the intersection of the
monitoring of all framing and plates from inside do sloping plate with the hatch side girder. The existing
not require permanent means of access of the cross longitudinal structure, if fitted on the sloping plate in
deck. the space may be used as part of this means of ac-
cess.
Alternatively, movable means of access may be util-
ized for access to the overhead structure of the cross For topside tanks of which the height is less than
deck if its vertical distance is 17 m or less above the 6 m, alternative means as defined in 3.9 or portable
tank top. means may be utilized in lieu of the permanent means
of access.

Access to vertical structures Bilge hopper tanks

Permanent means of vertical access shall be pro- For each bilge hopper tank of which the height is 6 m
vided in all cargo holds and built into the structure and over, one longitudinal continuous permanent
to allow for an inspection of a minimum of 25 % of means of access shall be provided along the side
the total number of hold frames port and starboard shell webs and installed at a minimum of 1,2 m be-
equally distributed throughout the hold including at low the top of the clear opening of the web ring with
each end in way of transverse bulkheads. But in no a vertical access ladder in the vicinity of each access
circumstance shall this arrangement be less than 3 to the tank.
permanent means of vertical access fitted to each
side (fore and aft ends of hold and mid-span). Per- An access ladder between the longitudinal continu-
manent means of vertical access fitted between two ous permanent means of access and the bottom of the
adjacent hold frames is counted for an access for the space shall be provided at each end of the tank.
inspection of both hold frames. A means of portable Alternatively, the longitudinal continuous permanent
access may be used to gain access over the sloping means of access can be located through the upper
plating of lower hopper ballast tanks. web plating above the clear opening of the web ring,
In addition, portable or movable means of access at a minimum of 1,6 m below the deck head, when
shall be utilized for access to the remaining hold this arrangement facilitates more suitable inspection
frames up to their upper brackets and transverse of identified structurally critical areas. An enlarged
bulkheads. longitudinal frame can be used for the purpose of the
walkway.
I - Part 1 Section 21 N Hull Outfit Chapter 1
GL 2012 Page 21–19

Table 21.7 Means of access for bulk carriers (continued)

Cargo holds Ballast tanks

Portable or movable means of access may be utilized For double-side skin bulk carriers, the longitudinal
for access to hold frames up to their upper bracket continuous permanent means of access may be in-
in place of the permanent means as required above. stalled within 6 m from the knuckle point of the bilge,
These means of access shall be carried on board the if used in combination with alternative methods to
ship and readily available for use. gain access to the knuckle point.
The width of vertical ladders for access to hold If no access holes are provided through the trans-
frames shall be at least 300 mm, measured between verse ring webs within 600 mm of the tank base and
stringers. the web frame rings have a web height greater than
1 m in way of side shell and sloping plating, then
A single vertical ladder over 6 m in length is accept- step rungs/grab rails shall be provided to allow safe
able for the inspection of the hold side frames in a access over each transverse web frame ring.
single skin construction.
For bilge hopper tanks of which the height is less
For double-side skin construction no vertical lad- than 6 m, alternative means as defined in 3.9 or
ders for the inspection of the cargo hold surfaces are portable means may be utilized in lieu of the perma-
required. Inspection of this structure should be pro- nent means of access. Such means of access shall be
vided from within the double hull space. demonstrated that they can be deployed and made
readily available in the areas where needed.

Double-skin side tanks

Permanent means of access shall be provided in ac-
cordance with the applicable sections of Tables 21.6.

Fore peak tanks

For fore peak tanks with a depth of 6 m or more at
the centreline of the collision bulkhead, a suitable
means of access shall be provided for access to criti-
cal areas such as the underdeck structure, stringers,
collision bulkhead and side shell structure.
Stringers of less than 6 m in vertical distance from
the deck head or a stringer immediately above are
considered to provide suitable access in combination
with portable means of access.
In case the vertical distance between the deck head
and stringers, stringers or the lowest stringer and the
tank bottom is 6 m or more, alternative means of ac-
cess as defined in 3.9 shall be provided.

3.13 For bulk carriers, access ladders to cargo clined ladder or series of inclined ladders at one end
holds and other spaces shall be: of the cargo hold, except the uppermost 2,5 m of a
cargo space measured clear of overhead obstructions

new Section 27, D.5.5.13 and the lowest 6 m may have vertical ladders, pro-
vided that the vertical extent of the inclined ladder or
3.13.1 Where the vertical distance between the up- ladders connecting the vertical ladders is not less than
per surface of adjacent decks or between deck and the 2,5 m.
bottom of the cargo space is not more than 6 m, either
a vertical ladder or an inclined ladder.
The second means of access at the other end of the

new Section 27, D.5.5.13.1 cargo hold may be formed of a series of staggered
vertical ladders, which should comprise of one or
3.13.2 Where the vertical distance between the up- more ladder linking platforms spaced not more than
per surface of adjacent decks or between deck and the 6 m apart vertically and displaced to one side of the
bottom of the cargo space is more than 6 m, an in- ladder. Adjacent sections of ladder should be laterally
Chapter 1 Section 21 N Hull Outfit I - Part 1
Page 21–20 GL 2012

offset from each other by at least the width of the head obstructions and comprise a ladder linking plat-
ladder. The uppermost entrance section of the ladder form, displaced to one side of a vertical ladder. The ver-
directly exposed to a cargo hold should be vertical for tical ladder can be between 1,6 m and 3 m below deck
a distance of 2,5 m measured clear of overhead ob- structure if it lands on a longitudinal or athwartship
structions and connected to a ladder-linking platform. permanent means of access fitted within that range.

new Section 27, D.5.5.13.2
new Section 27, D.5.5.14
3.13.3 A vertical ladder may be used as a means of
access to topside tanks, where the vertical distance is 4. Ship structure access manual
6 m or less between the deck and the longitudinal
means of access in the tank or the stringer or the bot- 4.1 A ship's means of access to carry out overall
tom of the space immediately below the entrance. The and close-up inspections and thickness measurements
uppermost entrance section from deck of the vertical shall be described in a Ship structure access manual
ladder of the tank should be vertical for a distance of approved by the Administration, an updated copy of
2,5 m measured clear of overhead obstructions and which shall be kept on board. The Ship structure ac-
comprise a ladder linking platform, unless landing on cess manual shall include the following for each space
the longitudinal means of access, the stringer or the in the cargo area:
bottom within the vertical distance, displaced to one
side of a vertical ladder. – plans showing the means of access to the space,

new Section 27, D.5.5.13.3 with appropriate technical specifications and
dimensions.
3.13.4 Unless allowed in 3.13.3 above, an inclined
ladder or combination of ladders should be used for – plans showing the means of access within each
access to a tank or a space where the vertical distance space to enable an overall inspection to be car-
is greater than 6 m between the deck and a stringer ried out, with appropriate technical specifica-
immediately below the entrance, between stringers, or tions and dimensions. The plans shall indicate
between the deck or a stringer and the bottom of the from where each area in the space can be in-
space immediately below the entrance. spected.

new Section 27, D.5.5.13.4 – plans showing the means of access within the
space to enable close-up inspections to be car-
3.13.5 In case of 3.13.4 above, the uppermost en- ried out, with appropriate technical specifica-
trance section from deck of the ladder should be verti- tions and dimensions. The plans shall indicate
cal for a distance of 2,5 m clear of overhead obstruc- the positions of critical structural areas, whether
tions and connected to a landing platform and contin- the means of access is permanent or portable
ued with an inclined ladder. The flights of inclined and from where each area can be inspected.
ladders should not be more than 9 m in actual length
and the vertical height should not normally be more – instructions for inspecting and maintaining the
than 6 m. The lowermost section of the ladders may be structural strength of all means of access and
vertical for a distance of not less than 2,5 m. means of attachment, taking into account any
corrosive atmosphere that may be within the

new Section 27, D.5.5.13.5 space
3.13.6 In double-side skin spaces of less than 2,5 m – instructions for safety guidance when rafting is
width, the access to the space may be by means of used for close-up inspections and thickness
vertical ladders that comprise of one or more ladder- measurements
linking platforms spaced not more than 6 m apart
vertically and displaced to one side of the ladder. – instructions for the rigging and use of any port-
Adjacent sections of ladder should be laterally offset able means of access in a safe manner
from each other by at least the width of the ladder.
– an inventory of all portable means of access

new Section 27, D.5.5.13.6
– records of periodical inspections and mainte-
3.13.7 A spiral ladder is considered acceptable as nance of the ship's means of access
an alternative for inclined ladders. In this regard, the
uppermost 2,5 m can continue to be comprised of the
new Section 27, D.5.4.1
spiral ladder and need not change over to vertical 4.2 For the purpose of these regulations "critical
ladders. structural areas" are locations which have been identi-
fied from calculations to require monitoring or from

new Section 27, D.5.5.13.7 the service history of similar or sister ships to be sensi-
tive to cracking, buckling, deformation or corrosion
3.14 The uppermost entrance section from deck of which would impair the structural integrity of the ship.
the vertical ladder providing access to a tank should be
vertical for a distance of 2,5 m measured clear of over-
new Section 27, D.5.4.2
I - Part 1 Section 21 P Hull Outfit Chapter 1
GL 2012 Page 21–21

5. Guard-rail stanchions are not to be welded to

5. Other Regulations and Recommendations the shell plating.

covered by new N
Attention is drawn to Chapter 6 of the "Guidelines for
the Inspection and Maintenance of Double Hull
Tanker Structures", Tanker Structure Co-operative 6. The use of doubling plates below guard-rail
Forum 1995. stanchions is permitted, if the dimensions are according
to Fig. 21.2 and the fatigue requirements in Section 20

new Section 27, D.5.6 are fulfilled (see respective detail in Table 20.5).

covered by new N

O. Guard-Rails Tube FB

tD ³ 2 t1 tD ³ t1 . 1,2
t1
1. Efficient guard-rails or bulwarks are to be b £ tD b £ tD
fitted on all exposed parts of the freeboard and super- (t1)
b b
structure decks.

tD

tD
The height is to be at least 1,0 m from the deck.

covered by new N
Fig. 21.2 Plates below guard-rail stanchions
2. The height below the lowest course of the
guard-rails is not to exceed 230 mm.

The other courses are not to be spaced more than P. Accesses to Ships
380 mm apart.
The design appraisal and testing of accesses to ships

covered by new N (accommodation ladders, gangways) are not part of
Classification.
3. In the case of ships with rounded gunwales However, approval of substructures in way of accommo-
the guard-rail supports are to be placed on the flat part dation ladders and gangways is part of Classification.
of the deck.

new Section 27, D.1.3

covered by new N
Note
4. Guard-rails are to be constructed in accor- For ships subject to the requirements of See-Berufs-
dance with DIN 81702 or equivalent standards. genossenschaft the GL Guidelines for the Construction
and Testing of Accesses to Ships (VI-2-4) apply. These
Equivalent constructions of sufficient strength and Guidelines will be applied in all cases where GL is
safety can be accepted. entrusted with the judgement of accesses to ships.

covered by new N
new Section 27, D.1.3 Note
I - Part 1 Section 22 B Structural Fire Protection Chapter 1
GL 2012 Page 22–1

Section 22

Structural Fire Protection

in this Section are no changes in numbering – Door plan

– Window plan

A. General – Fire control plan (for information only)

– List of approved materials and equipment

1. Application, submission of plans – General Arrangement (for information only)

Additional drawings for passenger ships
1.1 The requirements of this Section apply to
ships for unrestricted service. Ships intended for re- – Escape way plan incl. escape way calculation
stricted service or ships not subject to SOLAS may
– Evacuation analysis (only Ro-Ro passenger
diverge from the requirements provided that an ade-
ships)
quate level of safety is ensured. 1
– Fire load calculation
1.2 The terms used in this Section correspond to
the definitions as per Chapter II–2, Regulation 3 of 1.6 Type "A", "B" and "C" class partitions, fire
SOLAS 74. dampers, duct penetrations as well as the insulation
materials, linings, ceilings, surface materials and not
1.3 The term "Approved" relates to a material or readily ignitable deck coverings shall be of approved
construction, for which GL has issued an Approval type.
Certificate. A type approval can be issued on the basis
of a successful standard fire test, which has been car- 1.7 For regulations on fire alarm systems and on
ried out by a neutral and recognized fire testing insti- fire extinguishing arrangements, see the GL Rules for
tute. Machinery Installations (I-1-2), Section 12.

1.4 The fire safety design and arrangements may 1.8 IACS Unified Interpretations have to be ob-
differ from the prescriptive regulations of this Section, served and shall be complied with.
provided that the design and arrangements meet the
fire safety objectives and functional requirements of
Chapter II-2 of SOLAS 74 2. Compliance of the alter-
native design and arrangements needs to be verified B. Passenger Ships carrying more than 36
by an engineering analysis. Passengers

1.5 The following drawings and documents are to 1. Materials

be submitted for review.
1.1 The hull, decks, structural bulkheads, super-
– Fire division plan structures and deckhouses are to be of steel or other
equivalent material (Aluminium alloy suitably insu-
– Insulation plan lated).
– Joiner plan
1.2 Components made from aluminium alloys
– Ventilation and Air condition scheme require special treatment, with regard to the mechani-
cal properties of the material in case of temperature
– Deck covering plan increase. In principle, the following is to be observed:

1.2.1 The insulation of "A" or "B" class divisions

1 Reference is made to the "No. 99 Recommendation for the
shall be such that the temperature of the structural core
Safety of Cargo Vessels of less than Convention Size (IACS does not rise more than 200 °C above the ambient
Rec. 2007)" or equivalent. temperature at any time during the applicable fire
2 Reference is made to the "Guidelines on Alternative Design exposure to the standard fire test.
and Arrangements for Fire Safety" adopted by IMO by MSC/
Circ.1002
Chapter 1 Section 22 B Structural Fire Protection I - Part 1
Page 22–2 GL 2012

1.2.2 Special attention shall be given to the insula- provided and specifically approved. Service spaces
tion of aluminium alloy components of columns, stan- and ship stores shall not be located on ro-ro decks
chions and other structural members required to sup- unless protected in accordance with the applicable
port lifeboat and liferaft stowage, launching and em- regulations.
barkation areas, and "A" and "B" class divisions to
ensure: 3. Bulkheads within main vertical zones
that for such members supporting lifeboat and liferaft
areas and "A" class divisions, the temperature rise limi- 3.1 All bulkheads which are not required to be
tation specified in 1.2.1 shall apply at the end of one "A" class divisions shall be at least "B" class or "C"
hour; and class divisions as prescribed in Table 22.1. All such
divisions may be faced with combustible materials.
that for such members required to support "B" class
divisions, the temperature rise limitation specified in
3.2 All bulkheads required to be "B" class divi-
1.2.1 shall apply at the end of half an hour.
sion shall extend from deck to deck and to the shell or
other boundaries unless the continuous "B" class ceil-
1.2.3 Crowns and casings of machinery spaces of
ings or linings fitted on both sides of the bulkheads are
category A shall be of steel construction and be insu-
at least of the same fire resistance as the bulkhead, in
lated as required by Table 22.1 as appropriate. Open-
which case the bulkheads may terminate at the con-
ings therein, if any, shall be suitably arranged and
tinuous ceiling or lining.
protected to prevent the spread of fire.

2. Main vertical zones and horizontal zones 4. Fire integrity of bulkheads and decks

2.1 The hull, superstructure and deckhouses are 4.1 In addition to complying with the specific
to be subdivided into main vertical zones the average provisions for fire integrity of bulkheads and decks
length and width of which on any deck is generally mentioned elsewhere in this Part, the minimum fire
not to exceed 40 m. integrity of all bulkheads and decks shall be as pre-
scribed in Table 22.1 to 22.2.
Subdivision is to be effected by "A-60" class divi-
sions. Steps and recesses shall be kept to a minimum. 4.2 The following requirements shall govern
Where a category 4.3 [5], 4.3 [9] or 4.3 [10] space is application of the tables.
on one side of the division or where fuel oil tanks are
on both sides of the division the standard may be re- Table 22.1 shall apply to bulkheads and walls not
duced to "A-0". bounding either main vertical zones or horizontal
zones.
As far as practicable, the bulkheads forming the bound-
aries of the main vertical zones above the bulkhead Table 22.2 shall apply to decks not forming steps in
deck shall be in line with watertight subdivision bulk- main vertical zones nor bounding horizontal zones.
heads situated immediately below the bulkhead deck.
The length and width of main vertical zones may be 4.3 For the purpose of determining the appro-
extended to a maximum of 48 m in order to bring the priate fire integrity standards to be applied to bound-
ends of main vertical zones to coincide with subdivi- aries between adjacent spaces, such spaces are clas-
sion watertight bulkheads or in order to accommodate sified according to their fire risk as shown in the
a large public space extending for the whole length of following categories 1 to 14. Where the contents and
the main vertical zone provided that the total area of use of a space are such that there is a doubt as to
its classification for the purpose of this regulation,
the main vertical zone is not greater than 1600 m2 on
or where it is possible to assign two or more classi-
any deck. The length or width of a main vertical zone
fications to a space, it shall be treated as a space
is the maximum distance between the furthermost
within the relevant category having the most stringent
points of the bulkheads bounding it.
boundary requirements. Smaller, enclosed rooms
The divisions are to be extended from deck to deck within a space that have less than 30 % communi-
and to the shell or other boundaries. At the edges cating openings to that space are to be considered
insulating bridges are to be provided where required. separate spaces. The fire integrity of the boundary
bulkheads of such smaller rooms shall be as pre-
2.2 On ships designed for special purposes scribed in Tables 22.1 and 22.2. The title of each
(automobile or railroad car ferries), where the provi- category is intended to be typical rather than restric-
sion of main vertical zone bulkheads would defeat the tive. The number in parentheses preceding each cate-
purpose for which the ship is intended, equivalent gory refers to the applicable column or row number in
means for controlling and limiting a fire are to be the tables.
I - Part 1 Section 22 B Structural Fire Protection Chapter 1
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Table 22.1 Bulkheads not bounding either main vertical zones or horizontal zones

Spaces [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14]

Control stations [1] B–01 A–0 A–0 A–0 A–0 A–60 A–60 A–60 A–0 A–0 A–60 A–60 A–60 A–60
Stairways [2] A–01 A–0 A–0 A–0 A–0 A–15 A–15 A–03 A–0 A–15 A–30 A–15 A–30
Corridors [3] B–15 A–60 A–0 B–15 B–15 B–15 B–15 A–0 A–15 A–30 A–0 A–30
Evacuation sta- [4] A–0 A– A– A– A–04 A–0 A– A– A– A–
tions and external 602,4 60 2,4 602,4 602 602 602 602
escape routes
Open deck spaces [5] – A–0 A–0 A–0 A–0 A–0 A–0 A–0 A–0 A–0
Accommodation [6] B–0 B–0 B–0 C A–0 A–0 A–30 A–0 A–30
spaces of minor
fire risk
Accommodation [7] B–0 B–0 C A–0 A–15 A–60 A–15 A–60
spaces of moder-
ate fire risk
Accommodation [8] B–0 C A–0 A–30 A–60 A–15 A–60
spaces of greater
fire risk
Sanitary and simi- [9] C A–0 A–0 A–0 A–0 A–0
lar spaces
Tanks, voids and [10] A–01 A–0 A–0 A–0 A–0
auxiliary machin-
ery spaces having
little or no fire
risk
Auxiliary machin- [11] A–01 A–0 A–0 A–15
ery spaces, cargo
spaces, cargo and
other oil tanks and
other similar
spaces of moder-
ate fire risk
Machinery spaces [12] A–01 A–0 A–60
and main galleys
Store-rooms, work- [13] A–01 A–0
shops, pantries, etc.
other spaces in [14] A–30
which flammable
liquids are stowed

Notes to be applied to Table 22.1 to 22.2, as appropriate.

1 Where adjacent spaces are in the same numerical category and superscript 1 appears, a bulkhead or deck between such spaces need not
be fitted. For example, in category [12] a bulkhead need not be required between a galley and its annexed pantries provided the pantry
bulkhead and decks maintain the integrity of the galley boundaries. A bulkhead is, however, required between a galley and a machinery
space even though both spaces are in category [12].
2 The ship’s side, to the waterline in the lightest seagoing condition, superstructure and deckhouse sides situated below and adjacent to the
liferafts and evacuation slides may be reduced to "A-30".
3 Where public toilets are installed completely within the stairway enclosure, the public toilet bulkhead within the stairway enclosure can
be of "B" class integrity.
4 Where spaces of category [6], [7], [8] and [9] are located completely within the outer perimeter of the muster station, the bulkheads of
these spaces are allowed to be of "B-0" class integrity. Control positions for audio, video and light installations may be considered as
part of the muster station.
Chapter 1 Section 22 B Structural Fire Protection I - Part 1
Page 22–4 GL 2012

Table 22.2 Decks not forming steps in main vertical zones nor bounding zones

Spaces above
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14]
Spaces below
Control stations [1] A–30 A–30 A–15 A–0 A–0 A–0 A–15 A–30 A–0 A–0 A–0 A–60 A–0 A–60
Stairways [2] A–0 A–0 – A–0 A–0 A–0 A–0 A–0 A–0 A–0 A–0 A–30 A–0 A–30
Corridors [3] A–15 A–0 A–01 A–60 A–0 A–0 A–15 A–15 A–0 A–0 A–0 A–30 A–0 A–30
Evacuation stations [4] A–0 A–0 A–0 A–0 – A–0 A–0 A–0 A–0 A–0 A–0 A–0 A–0 A–0
and external escape
routes
Open deck spaces [5] A–0 A–0 A–0 A–0 – A–0 A–0 A–0 A–0 A–0 A–0 A–0 A–0 A–0
Accommodation [6] A–60 A–15 A–0 A–60 A–0 A–0 A–0 A–0 A–0 A–0 A–0 A–0 A–0 A–0
spaces of minor fire
risk
Accommodation [7] A–60 A–15 A–15 A–60 A–0 A–0 A–15 A–15 A–0 A–0 A–0 A–0 A–0 A–0
spaces of moderate
fire risk
Accommodation [8] A–60 A–15 A–15 A–60 A–0 A–15 A–15 A–30 A–0 A–0 A–0 A–0 A–0 A–0
spaces of greater
fire risk
Sanitary and simi- [9] A–0 A–0 A–0 A–0 A–0 A–0 A–0 A–0 A–0 A–0 A–0 A–0 A–0 A–0
lar spaces
Tanks, voids and [10] A–0 A–0 A–0 A–0 A–0 A–0 A–0 A–0 A–0 A–01 A–0 A–0 A–0 A–0
auxiliary machin-
ery spaces having
little or no fire risk
Auxiliary machin- [11] A–60 A–60 A–60 A–60 A–0 A–0 A–15 A–30 A–0 A–0 A–01 A–0 A–0 A–30
ery spaces, cargo
spaces, cargo and
other oil tanks and
other similar spaces
of moderate fire risk
Machinery spaces [12] A–60 A–60 A–60 A–60 A–0 A–60 A–60 A–60 A–0 A–0 A–30 A–301 A–0 A–60
and main galleys
Store-rooms, work- [13] A–60 A–30 A–15 A–60 A–0 A–15 A–30 A–30 A–0 A–0 A–0 A–0 A–0 A–0
shops, pantries, etc.
Other spaces in [14] A–60 A–60 A–60 A–60 A–0 A–30 A–60 A–60 A–0 A–0 A–0 A–0 A–0 A–0
which flammable
liquids are stowed
See Notes under Table 22.1.

[1] Control stations wholly contained within the machinery spaces)

for passengers and crew and enclosures thereto.
Spaces containing emergency sources of power
and lighting. Wheelhouse and chartroom. Spaces In this connection, a stairway which is enclosed
containing the ship's radio equipment. Fire con- at only one level shall be regarded as part of the
trol stations. Control room for propulsion ma- space from which it is not separated by a fire
chinery when located outside the propulsion ma- door.
chinery space. Spaces containing centralized fire
alarm equipment. Spaces containing centralized [3] Corridors
emergency public address system stations and
Passenger and crew corridors and lobbies.
equipment.

[2] Stairways [4] Evacuation stations and external escape

routes.
Interior stairways, lifts, totally enclosed emergen-
cy escape trunks and escalators (other than those Survival craft stowage area.
I - Part 1 Section 22 B Structural Fire Protection Chapter 1
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Open deck spaces and enclosed promenades Private sanitary facilities shall be considered a
forming lifeboat and liferaft embarkation and portion of the space in which they are located.
lowering stations.
[10] Tanks, voids and auxiliary machinery spaces
Assembly stations, internal and external. having little or no fire risk
External stairs and open decks used for escape Water tanks forming part of the ship's structure.
routes. Voids and cofferdams. Auxiliary machinery
The ship's side to the waterline in the lightest sea- spaces which do not contain machinery having a
going condition, superstructure and deckhouse pressure lubrication system and where storage of
sides situated below and adjacent to the liferafts combustibles is prohibited, such as:
and evacuation slide's embarkation areas. Ventilation and air-conditioning rooms; wind-
lass room; steering gear room; stabilizer equip-
[5] Open deck spaces ment room; electrical propulsion motor room;
Open deck spaces and enclosed promenades rooms containing section switchboards and
clear of lifeboat and liferaft embarkation and purely electrical equipment other than oil-filled
lowering stations. To be considered in this cate- electrical transformers (above 10 kVA); shaft
gory, enclosed promenades shall have no sig- alleys and pipe tunnels; spaces for pumps and
nificant fire risk, meaning that furnishings shall refrigeration machinery (not handling or using
be restricted to deck furniture. In addition, such flammable liquids).
spaces shall be naturally ventilated by perma- Closed trunks serving the spaces listed above.
nent openings. Air spaces (the space outside su- Other closed trunks such as pipe and cable trunks.
perstructures and deckhouses).
[11] Auxiliary machinery spaces, cargo spaces,
[6] Accommodation spaces of minor fire risk cargo and other oil tanks and other similar
spaces of moderate fire risk
Cabins containing furniture and furnishings of
restricted fire risk. Offices and dispensaries con- Cargo oil tanks. Cargo holds, trunkways and
taining furniture and furnishings of restricted hatchways. Refrigerated chambers. Oil fuel
fire risk. Public spaces containing furniture and tanks (where installed in a separate space with
furnishings of restricted fire risk and having a no machinery). Shaft alleys and pipe tunnels al-
deck area of less than 50 m2. lowing storage of combustibles. Auxiliary ma-
chinery spaces as in category 10 which contain
[7] Accommodation spaces of moderate fire risk machinery having a pressure lubrication system
or where storage of combustibles is permitted.
Spaces as in category 6 above but containing
Oil fuel filling stations. Spaces containing oil-
furniture and furnishings of other than restricted
filled electrical transformers (above 10 kVA).
fire risk. Public spaces containing furniture and
Spaces containing turbine and reciprocating
furnishings of restricted fire risk and having a
steam engine driven auxiliary generators and
deck area of 50 m2 or more. Isolated lockers and small internal combustion engines of power out-
small store-rooms in accommodation spaces put up to 110 kW driving generators, sprinkler,
having areas less than 4 m2 (in which flammable drencher or fire pumps, bilge pumps, etc. Closed
liquids are not stowed). Sale shops. Motion pic- trunks serving the spaces listed above.
ture projection and film stowage rooms. Diet
kitchens (containing no open flame). Cleaning [12] Machinery spaces and main galleys
gear lockers (in which flammable liquids are not
stowed). Laboratories (in which flammable liq- Main propulsion machinery rooms (other than
uids are not stowed). Pharmacies. Small drying electric propulsion motor rooms) and boiler
rooms (having a deck area of 4 m2 or less). Spe- rooms. Auxiliary machinery spaces other than
cie rooms, operating rooms, electrical distribu- those in categories 10 and 11 which contain in-
tion boards (see 4.3.2 and 4.3.3). ternal combustion machinery or other oil-burn-
ing, heating or pumping units. Main galleys and
[8] Accommodation spaces of greater fire risk annexes. Trunks and casings to the spaces listed
above.
Public spaces containing furniture and furnish-
ings of other than restricted fire risk and having [13] Store-rooms, workshops, pantries, etc.
a deck area of 50 m2 or more. Barber shops and Main pantries not annexed to galleys. Main
beauty parlours. Saunas. laundry. Large drying rooms (having a deck area
of more than 4 m2). Miscellaneous stores. Mail
[9] Sanitary and similar spaces
and baggage rooms. Garbage rooms. Workshops
Communal sanitary facilities, showers, baths, (not part of machinery spaces, galleys, etc.),
water closets, etc. Small laundry rooms. Indoor lockers and store-rooms having areas greater
swimming pool area. Isolated pantries containing than 4 m2, other than those spaces which have
no cooking appliances in accommodation spaces. provisions for the storage of flammable liquids.
Chapter 1 Section 22 B Structural Fire Protection I - Part 1
Page 22–6 GL 2012

[14] Other spaces in which flammable liquids are 5.1.2 Stairways fitted within a closed public space
stowed need not be enclosed.
Lamp rooms. Paint rooms. Store-rooms contain- 5.2 Stairway enclosures are to be directly acces-
ing flammable liquids (including dyes, medi- sible from the corridors and of sufficient area to pre-
cines, etc.). Laboratories (in which flammable vent congestion, having in mind the number of persons
liquids are stowed). likely to use them in an emergency. Within the peri-
meter of such stairway enclosures, only public toilets,
4.3.1 In respect of category [5] spaces Germani-
lockers of non-combustible material providing storage
scher Lloyd shall determine whether the insulation
for safety equipment and open information counters
values in Table 22.1 shall apply to ends of deckhouses
are permitted. Only corridors, public toilets, special
and superstructures, and whether the insulation values
category spaces, other escape stairways required by
in Table 22.2 shall apply to weather decks. In no case
12.3.3 and external areas are permitted to have direct
shall the requirements of category [5] of Table 22.1 or
access to these stairway enclosures. Public spaces may
22.2 necessitate enclosure of spaces which in the opin-
also have direct access to stairways enclosures except
ion of Germanischer Lloyd need not be enclosed.
for the backstage of a theatre.
4.3.2 Electrical distribution boards may be located Small corridors or lobbies used to separate an en-
behind panels/linings within accommodation spaces in- closed stairway from galleys or main laundries may
cluding stairway enclosures, without the need to catego- have direct access to the stairway provided they have a
rize the space, provided no provision for storage is made. minimum deck area of 4,5 m2, a width of no less than
900 mm and contain a fire hose station.
4.3.3 If distribution boards are located in an identi-
fiable space having a deck area of less than 4 m2, this 5.3 Lift trunks shall be so fitted as to prevent the
space shall be categorized in (7). passage of smoke and flame from one 'tween deck to
another and shall be provided with means of closing
4.4 Continuous "B" class ceilings or linings, in so as to permit the control of draught and smoke.
association with the relevant decks or bulkheads, may
be accepted as contributing wholly or in part, to the 6. Openings in "A" class divisions
required insulation and integrity of a division.
6.1 Where "A" class divisions are penetrated for
4.5 At intersections and terminal points of the the passage of electric cables, pipes, trunks, ducts, etc.,
required fire insulation constructions due regard is to or for girders, beams or other structural members, ar-
be paid to the effect of thermal bridges. In order to rangements shall be made to ensure that the fire resis-
avoid this, the insulation of a deck or bulkhead shall tance is not impaired, subject to the provisions of 6.7.
be carried past the intersection or terminal point for a 6.2 All openings in the divisions are to be pro-
distance of at least 450 mm. vided with permanently attached means of closing
which shall be at least as effective for resisting fire as
4.6 Protection of atriums the divisions This does not apply for hatches between
4.6.1 Atriums shall be within enclosures formed of cargo, special category, store and baggage spaces and
"A" class divisions having a fire rating determined in between such spaces and the weather decks.
accordance with Table 22.2, as applicable. 6.3 The construction of all doors and door frames
in "A" class divisions, with the means of securing
4.6.2 Decks separating spaces within atriums shall
them when closed, shall provide resistance to fire as
have a fire rating determined in accordance with Table
well as to the passage of smoke and flame equivalent
22.2, as applicable.
to that of the bulkheads in which the doors are situ-
ated 3. Such doors and door frames shall be approved
5. Protection of stairways and lifts in ac- by GL and constructed of steel or other equivalent
commodation and service spaces material. Doors approved without the sill being part of
the frame, which are installed on or after 1 July 2010,
5.1 All stairways in accommodation and service
shall be installed such that the gap under the door does
spaces are to be of steel frame or other approved
not exceed 12 mm. A non-combustible sill shall be
equivalent construction; they are to be arranged within
installed under the door such that floor coverings do
enclosures formed by "A" class division, with effec-
not extend beneath the closed door.
tive means of closure for all openings.
The following exceptions are admissible: 6.4 Watertight doors need not be insulated.

5.1.1 A stairway connecting only two decks need not

be enclosed, provided that the integrity of the pierced
deck is maintained by suitable bulkheads or doors at 3 Reference is made to the Fire Test Procedure Code, Annex 1,
one of the two decks. When a stairway is closed at one Part 3, adopted by IMO by Resolution MSC.61(67). On ships
constructed on or after 1 July 2012, the new Fire Test Procedure
'tween deck space, the stairway enclosure shall be Code, adopted by IMO by Resolution MSC.307(88), is appli-
protected in accordance with the tables for decks. cable.
I - Part 1 Section 22 B Structural Fire Protection Chapter 1
GL 2012 Page 22–7

6.5 It shall be possible for each door to be opened 6.6.11 A door designed to re-open upon contacting
and closed from each side of the bulkhead by one an object in its path shall re-open not more than 1 m
person only. from the point of contact.

6.6 Fire doors in main vertical zone bulkheads, 6.6.12 Double-leaf doors equipped with a latch
galley boundaries and stairway enclosures other than necessary to their fire integrity shall have a latch that
power-operated watertight doors and those which are is automatically activated by the operation of the
normally locked, shall satisfy the following require- doors when released by the control system.
ments:
6.6.13 Doors giving direct access to special category
6.6.1 The doors shall be self-closing and be capa- spaces which are power-operated and automatically
ble of closing against an angle of inclination of up to closed need not be equipped with the alarms and re-
3,5° opposing closure. mote-release mechanisms required in 6.6.3 and 6.6.10.
6.6.2 The approximate time of closure for hinged 6.6.14 The components of the local control system
fire doors shall be no more than 40 s and no less than shall be accessible for maintenance and adjusting.
10 s from the beginning of their movement with the
ship in upright position. The approximate uniform rate 6.6.15 Power-operated doors shall be provided with
of closure for sliding fire doors shall be of no more a control system of an approved type which shall be
than 0,2 m/s and no less than 0,1 m/s with the ship in able to operate in case of fire 3. This system shall
the upright position. satisfy the following requirements:
6.6.3 The doors, except those for emergency es- 6.6.15.1 the control system shall be able to operate
cape trunks shall be capable of remote release from the door at the temperature of at least 200 °C for at
the continuously manned central control station, either least 60 min, served by the power supply.
simultaneously or in groups and shall be capable of
release also individually from a position at both sides 6.6.15.2 the power supply for all other doors not sub-
of the door. Release switches shall have an on-off ject to fire shall nor be impaired; and
function to prevent automatic resetting of the system.
6.6.15.3 at temperatures exceeding 200 °C the control
6.6.4 Hold-back hooks not subject to central con- system shall be automatically isolated from the power
trol station release are prohibited. supply and shall be capable of keeping the door closed
6.6.5 A door closed remotely from the central control up to at least 945 °C.
station shall be capable of being re-opened at both sides 6.7 The requirements for "A" class integrity of the
of the door by local control. After such local opening, outer boundaries of a ship shall not apply to glass parti-
the door shall automatically close again (see also the GL tions, windows and sidescuttles, provided that there is
Rules for Electrical Installations (I-1-3), Section 9). no requirement for such boundaries to have "A" class
6.6.6 Indication shall be provided at the fire door integrity in 8.3. The requirements for "A" class integ-
indicator panel in the continuously manned central rity of the outer boundaries of the ship shall not apply
control station whether each of the remote-released to exterior doors, except for those in superstructures
doors are closed. and deckhouses facing life-saving appliances, embar-
kation and external muster station areas, external stairs
6.6.7 The release mechanism shall be so designed and open decks used for escape routes. Stairway enclo-
that the door will automatically close in the event of sure doors need not meet this requirement.
disruption of the control system or main source of
electric power. 6.8 Except for watertight, weathertight doors (semi-
watertight doors), doors leading to the open deck and
6.6.8 Local power accumulators for power- doors which need to be reasonably gastight, all "A" class
operated doors shall be provided in the immediate doors located in stairways, public spaces and main verti-
vicinity of the doors to enable the doors to be operated cal zone bulkheads in escape routes shall be equipped
after disruption of the control system or main source with a self-closing hose port of material, construction
of electric power at least ten times (fully opened and and fire resistance which is equivalent to the door into
closed) using the local controls (see also the GL Rules which it is fitted, and shall be a 150 mm square clear
for Machinery Installations (I-1-2), Section 14). opening with the door closed and shall be inset into the
6.6.9 Disruption of the control system or main lower edge of the door, opposite the door hinges, or in
source of electric power at one door shall not impair the case of sliding doors, nearest the opening.
the safe functioning of the other doors.
7. Openings in "B" class divisions
6.6.10 Remote-released sliding or power-operated
doors shall be equipped with an alarm that sounds for 7.1 Where "B" class divisions are penetrated for
at least 5 s but no more than 10 s after the door is the passage of electric cables, pipes, trunks, ducts,
released from the central control station and before the etc., or for the fitting of ventilation terminals, lighting
door begins to move and continue sounding until the fixtures and similar devices, arrangements shall be
door is completely closed. made to ensure that the fire resistance is not impaired.
Chapter 1 Section 22 B Structural Fire Protection I - Part 1
Page 22–8 GL 2012

Pipes other than steel or copper that penetrate "B" below liferaft and escape slide embarkation areas shall
class divisions shall be protected by either: have the fire integrity as required in the Tables 22.1 to
22.2. Where automatic dedicated sprinkler heads are
– a fire tested penetration device, suitable for the provided for windows (see also the GL Rules for Ma-
fire resistance of the division pierced and the chinery Installations (I-1-2), Section 12), A-0 windows
type of pipe used; or may be accepted as equivalent. Windows located in the
– a steel sleeve, having a thickness of not less than ship's side below the lifeboat embarkation areas shall
1,8 mm and a length of not less than 900 mm for have the fire integrity at least equal to "A-0" class.
pipe diameters of 150 mm or more and not less
than 600 mm for pipe diameters of less than 150 9. Ventilation systems
mm, preferably equally divided to each side of
9.1 In general, the ventilation fans shall be so
the division. The pipe shall be connected to the
disposed that the ducts reaching the various spaces
ends of the sleeve by flanges or couplings; or the
remain within the main vertical zone.
clearance between the sleeve and the pipe shall
not exceed 2,5 mm; or any clearance between 9.2 Where ventilation systems penetrate decks,
pipe and sleeve shall be made tight by means of precautions shall be taken, in addition to those relating
non-combustible or other suitable material. to the fire integrity of the deck required by 6. to re-
duce the likelihood of smoke and hot gases passing
7.2 Doors and door frames in "B" class divisions from one between deck space to another through the
and means of securing them shall provide a method of system. In addition to insulation requirements con-
closure which shall have resistance to fire equivalent tained in 9. vertical ducts shall, if necessary, be insu-
to that of the divisions 3 except that ventilation openings lated as required by the appropriate tables in 4.
may be permitted in the lower portion of such doors.
Where such opening is in or under a door the total net 9.3 The main inlets and outlets of all ventilation
area of any such opening or openings shall not exceed systems shall be capable of being closed from outside
0,05 m2. Alternatively, a non-combustible air balance the respective spaces in the event of a fire.
duct routed between the cabin and the corridor, and
located below the sanitary unit is permitted where the 9.4 Except in cargo spaces, ventilation ducts shall
cross-sectional area of the duct does not exceed 0,05 m2. be constructed of the following materials:
All ventilation openings shall be fitted with a grill made 9.4.1 Ducts not less than 0,075 m2 in sectional area
of non-combustible material. Doors shall be non-com- and all vertical ducts serving more than a single 'tween
bustible and approved by GL. Doors approved without deck space shall be constructed of steel or other
the sill being part of the frame, which are installed on equivalent material.
or after 1 July 2010, shall be installed such that the
gap under the door does not exceed 25 mm. 9.4.2 Ducts less than 0,075 m2 in sectional area
other than vertical ducts referred to in 9.4.1 shall be
7.3 Cabin doors in "B" class divisions shall be of constructed of steel or equivalent. Where such ducts
a self-closing type. Hold-backs are not permitted. penetrate "A" or "B" Class divisions due regard shall
be given to ensuring the fire integrity of the division.
7.4 The requirements for "B" class integrity of
the outer boundaries of a ship shall not apply to glass 9.4.3 Short lengths of duct, not in general exceed-
partitions, windows and sidescuttles. Similarly, the ing 0,02 m2 in sectional area nor 2 m in length, need
requirements for "B" class integrity shall not apply to not be steel or equivalent provided that all of the fol-
exterior doors in superstructures and deckhouses. lowing conditions are met:
9.4.3.1 Subject to 9.4.3.2 the duct is constructed of
8. Windows and sidescuttles
any material having low flame spread characteristics 4
8.1 All windows and sidescuttles in bulkheads which is type approved.
within accommodation and service spaces and control 9.4.3.2 on ships constructed on or after 1 July 2010, the
stations other than those to which the provisions of 6.6 ducts shall be made of heat resisting non-combustible
and of 7.4 apply, shall be so constructed as to pre- material, which may be faced internally and externally
serve the integrity requirements of the type of bulk- with membranes having low flame-spread characteris-
heads in which they are fitted.
tics and, in each case, a calorific value 5 not exceeding
8.2 Notwithstanding the requirements of the Tables 45 MJ/m2 of their surface area for the thickness used;
22.1 to 22.2 all windows and sidescuttles in bulkheads
separating accommodation and service spaces and 4
control stations from weather shall be constructed with Reference is made to the Fire Test Procedure Code, Annex 1,
Part 5, adopted by IMO by Resolution MSC.61(67). On ships
frames of steel or other suitable material. The glass constructed on or after 1 July 2012, the new Fire Test Procedure
shall be retained by a metal glazing bead or angle. Code, adopted by IMO by Resolution MSC.307(88), is appli-
cable.
8.3 Windows facing life-saving appliances, em- 5 Refer to the recommendations published by the International
barkation and muster areas, external stairs and open Organization for Standardization, in particular publication ISO
decks used for escape routes, and windows situated 1716 : 2002, Determination of calorific potential.
I - Part 1 Section 22 B Structural Fire Protection Chapter 1
GL 2012 Page 22–9

9.4.3.3 the duct is used only at the terminal end of and identification number should be placed also on
the ventilation system; and any remote control required.
9.4.3.4 the duct is not located closer than 0,6 m meas- 9.7.3 The following arrangement shall be of an
ured along its length to a penetration of an "A" or "B" approved type 3.
class division, including continuous "B" class ceilings.
9.7.3.1 Fire dampers, including relevant means of
9.5 Stairway enclosures shall be ventilated by an operation.
independent fan and duct system which shall not serve 9.7.3.2 Duct penetrations through "A" class divi-
any other spaces in the ventilation system. sions. Where steel sleeves are directly joined to venti-
lation ducts by means of riveted or screwed flanges or
9.6 All power ventilation, except machinery and by welding, the test is not required.
cargo spaces ventilation and any alternative system
which may be required under 9.9, shall be fitted with 9.8 Exhaust ducts from galley ranges in which
controls so grouped that all fans may be stopped from grease or fat is likely to accumulate shall meet the require-
either of two positions which shall be situated as far ments as mentioned in 9.11.2 and shall be fitted with:
apart as practicable. Controls provided for the power
ventilation serving machinery spaces shall also be 9.8.1 a grease trap readily removable for cleaning
grouped so as to be operable from two positions, one of unless an alternative approved grease removal system
which shall be outside such spaces. Fans serving power is fitted;
ventilation systems to cargo spaces shall be capable of 9.8.2 a fire damper located in the lower end of the
being stopped from a safe position outside such spaces. duct which is automatically and remotely operated,
and in addition a remotely operated fire damper lo-
9.7 Where a thin plated duct with a free cross- cated in the upper end of the duct;
sectional area equal to or less than 0,02 m2 passes
through "A" class bulkheads or decks, the opening 9.8.3 a fixed means for extinguishing a fire within
shall be lined with a steel sheet sleeve having a thick- the duct (see also the GL Rules for Machinery Instal-
ness of at least 3 mm and a length of at least 200 mm, lations (I-1-2), Section 12);
divided preferably into 100 mm on each side of the
9.8.4 remote control arrangements for shutting off
bulkhead or, in the case of the deck, wholly laid on the
the exhaust fans and supply fans, for operating the fire
lower side of the decks pierced.
dampers mentioned in 9.8.2 and for operating the fire-
Where ventilation ducts with a free cross-sectional extinguishing system, which shall be placed in a posi-
area exceeding 0,02 m2 pass through "A" class bulk- tion close to the entrance to the galley. Where a multi-
heads or decks, the opening shall be lined with a steel branch system is installed, means shall be provided to
sheet sleeve. However, where such ducts are of steel close all branches exhausting through the same main
construction and pass through a deck or bulkhead, the duct before an extinguishing medium is released into
ducts and sleeves shall comply with the following: the system; and

9.7.1 The sleeves shall have a thickness of at least 9.8.5 suitably located hatches for inspection and
3 mm and a length of at least 900 mm. When passing cleaning.
through bulkheads, this length shall be divided pref-
9.8.6 Exhaust ducts from ranges for cooking equip-
erably into 450 mm on each side of the bulkhead.
ment installed on open decks shall conform to para-
These ducts, or sleeves lining such ducts, shall be
graph 9.8 to 9.8.5, as applicable, when passing through
provided with fire insulation. The insulation shall have
accommodation spaces or spaces containing combusti-
at least the same fire integrity as the bulkhead or deck
ble materials.
through which the duct passes.
9.7.2 Ducts with a free cross-sectional area exceed- 9.9 Such measures as are practicable shall be
taken in respect of control stations outside machinery
ing 0,075 m2 shall be fitted with fire dampers in addi-
spaces in order to ensure that ventilation, visibility and
tion to the requirements of 9.7.1. The fire damper shall
freedom from smoke are maintained, so that in the
operate automatically but shall also be capable of
event of fire the machinery and equipment contained
being closed manually from both sides of the bulkhead
therein may be supervised and continue to function
or deck. The damper shall be provided with an indica-
effectively. Alternative and separate means of air
tor which shows whether the damper is open or
supply shall be provided; air inlets of the two sources
closed. Fire dampers are not required, however, where
of supply shall be so disposed that the risk of both
ducts pass through spaces surrounded by "A" class
inlets drawing in smoke simultaneously is minimized.
divisions, without serving those spaces, provided
Such requirements need not apply to control stations
those ducts have the same fire integrity as the divi-
situated on, and opening on to, an open deck.
sions which they pierce. The fire dampers should be
easily accessible. Where they are placed behind ceil- The ventilation system serving safety centres may be
ings and linings, these latter should be provided with derived from the ventilation system serving the navi-
an inspection door on which a plate reporting the gation bridge, unless located in an adjacent main ver-
identification number of the fire damper. Such plate tical zone.
Chapter 1 Section 22 B Structural Fire Protection I - Part 1
Page 22–10 GL 2012

9.10 The ventilation systems for machinery spaces 9.12.3 except that penetrations of main zone divi-
of category A, vehicle spaces, ro-ro spaces, galleys, sion shall also comply with the requirements in 9.14.
special category spaces and cargo spaces shall, in
general, be separated from each other and from the 9.13 Ventilation ducts with a free cross-sectional area
ventilation system serving other spaces. exceeding 0,02 m2 passing through "B" class bulkheads
shall be lined with steel sheet sleeves of 900 mm in
9.11 Ducts provided for the ventilation of machin- length divided preferably into 450 mm on each side of
ery spaces of category A, galleys, vehicle spaces, ro-ro the bulkheads unless the duct is of steel for this length.
cargo spaces or special category spaces shall not pass
through accommodation spaces, service spaces or con- 9.14 Where in a passenger ship it is necessary that
trol stations unless the ducts are either complying with a ventilation duct passes through a main vertical zone
9.11.1 or 9.11.2. division, a fail-safe automatic closing fire damper
shall be fitted adjacent to the division. The damper
9.11.1 constructed of steel having a thickness of at shall also be capable of being manually closed from
least 3 mm and 5 mm for ducts the widths or diame- each side of the division. The operating position shall
ters of which are up to and including 300 mm and be readily accessible and be marked in red light-
760 mm and over respectively and, in the case of such reflecting colour. The duct between the division and
ducts, the widths or diameters of which are between the damper shall be of steel or other equivalent mate-
300 mm and 760 mm having a thickness to be ob- rial and, if necessary, insulated to comply with the
tained by interpolation; requirements of 6.1. The damper shall be fitted on at
suitably supported and stiffened; least one side of the division with a visible indicator
showing whether the damper is in the open position.
fitted with automatic fire dampers close to the bounda-
ries penetrated; and 9.15 Power ventilation of accommodation spaces
insulated to "A-60" standard from the machinery service spaces, cargo spaces, control stations and ma-
spaces, galleys, vehicle spaces, ro-ro cargo spaces or chinery spaces shall be capable of being stopped from an
special category spaces to a point at least 5 m beyond easily accessible position outside the space being served.
each fire damper; or This position should not be readily cut off in the event
of a fire in the spaces served. The means provided for
9.11.2 constructed of steel suitable supported and stopping the power ventilation of the machinery
stiffened in accordance with 9.11.1 and spaces shall be entirely separate from the means pro-
vided for stopping ventilation of other spaces.
insulated to "A-60" standard throughout the accom-
modation spaces, service spaces or control stations; 9.16 Controls for shutting down the ventilation
fans shall be centralized in a continuously manned
9.11.3 except that penetrations of main zone divi- central control station. The ventilation fans shall be
sions shall also comply with the requirements of 9.14. capable of reactivation by the crew at this location,
whereby the control panels shall be capable of indicat-
9.12 Ducts provided for the ventilation to accommo- ing closed or off status of fans.
dation spaces, service spaces or control stations shall not
pass through machinery spaces of category A, galleys, 9.17 Exhaust ducts shall be provided with suitably
vehicle spaces, ro-ro cargo spaces or special category located hatches for inspection and cleaning. The
spaces unless either complying with 9.12.1 or 9.12.2. hatches shall be located near the fire damper.
9.12.1 the ducts where they pass through a machin- 9.18 Where public spaces span three or more open
ery space of category A, galley, vehicle space, ro-ro decks and contain combustibles such as furniture and
cargo space or special category space are constructed enclosed spaces such as shops, offices and restaurants,
of steel, suitable supported and stiffened in accordance the space shall be equipped with a smoke extraction
with 9.11.1 and system (see also the GL Rules for Machinery Installa-
automatic fire dampers are fitted close to the bounda- tions (I-1-2), Section 12).
ries penetrated; and
9.19 Exhaust ducts from main laundries shall be
integrity of the machinery space, galley, vehicle space, fitted with:
ro-ro cargo space or special category space boundaries
is maintained at the penetrations; or .1 filters readily removable for cleaning purposes;
.2 a fire damper located in the lower end of the duct
9.12.2 the ducts where they pass through a machin- which is automatically and remotely operated;
ery space of category A, galley, vehicle space, ro-ro
cargo space or special category space are constructed .3 remote-control arrangements for shutting off
of steel, suitable supported and stiffened in accordance the exhaust fans and supply fans from within
with 9.11.1 the space and for operating the fire damper
mentioned in 9.19.2; and
are insulated to "A-60" standard within the machinery
space galley, vehicle space, ro-ro cargo space or spe- .4 suitably located hatches for inspection and
cial category space; cleaning.
I - Part 1 Section 22 B Structural Fire Protection Chapter 1
GL 2012 Page 22–11

10. Restriction of combustible materials 10.6 Furniture in stairway enclosures shall be lim-
ited to seating. It shall be fixed, limited to six seats on
10.1 Except in cargo spaces, mail rooms, baggage each deck in each stairway enclosure, be of restricted fire
rooms, saunas 6 or refrigerated compartments of ser- risk, and shall not restrict the passenger escape route.
vice spaces, all linings, grounds, draught stops, ceil-
Furniture shall not be permitted in passenger and crew
ings and insulation's shall be of non-combustible ma-
corridors forming escape routes in cabin areas. Lockers
terials. Partial bulkheads or decks used to subdivide a
of non-combustible material, providing storage for
space for utility or artistic treatment shall also be of
safety equipment, may be permitted within these areas.
non-combustible material.
Drinking water dispensers and ice cube machines may
Linings, ceilings and partial bulkheads or decks used
be permitted in corridors provided they are fixed and
to screen or to separate adjacent cabin balconies shall
do not restrict the width of the escape route. This
be of non-combustible material.
applies as well to decorative flower arrangements,
10.2 Vapour barriers and adhesives used in con- statues or other objects d’art such as paintings and
junction with insulation, as well as insulation of pipe tapestries in corridors and stairways.
fittings, for cold service systems need not be non-
10.7 Furniture and furnishings on cabin balconies
combustible but they shall be kept to the minimum
shall comply with the following, unless such balconies
quantity practicable and their exposed surfaces shall
are protected by a fixed pressure water-spraying and
have low flame spread characteristics.
fixed fire detection and fire alarm systems
10.3 The following surfaces shall have low flame- 10.7.1 case furniture shall be constructed entirely of
spread characteristics 4: approved non-combustible materials, except that a
combustible veneer not exceeding 2 mm may be used
10.3.1 exposed surfaces in corridors and stairway on the working surface;
enclosures, and of bulkheads, wall and ceiling linings
in accommodation and service spaces (except saunas) 10.7.2 free-standing furniture shall be constructed
and control stations; with frames of non-combustible materials;
10.3.2 concealed or inaccessible spaces in accom- 10.7.3 draperies and other suspended textile materi-
modation, service spaces and control stations, als shall have qualities of resistance to the propagation
of flame not inferior to those of wool having a mass of
10.3.3 exposed surfaces of cabin balconies, except 0,8 kg/m2 8;
for natural hard wood decking systems.
10.7.4 upholstered furniture shall have qualities of
10.4 The total volume of combustible facings,
resistance to the ignition and propagation of flame 9 and
mouldings, decorations and veneers in any accommo-
dation and service space shall not exceed a volume 10.7.5 bedding components shall have qualities of
equivalent to 2,5 mm veneer on the combined area of resistance to the ignition and propagation of flame 10.
the walls and ceilings. Furniture fixed to linings, bulk-
heads or decks need not be included in the calculation 10.8 Paints, varnishes and other finishes used on
of the total volume of combustible materials. This exposed interior surfaces, including cabin balconies
applies also to traditional wooden benches and wood- with the exclusion of natural hard wood decking sys-
en linings on bulkheads and ceilings in saunas. In the tems, shall not be capable of producing excessive
case of ships fitted with an automatic sprinkler system, quantities of smoke and toxic products 11.
the above volume may include some combustible
material used for erection of "C" class divisions.
8 Reference is made to the Fire Test Procedure Code, Annex 1,
10.5 Combustible materials used on surfaces and Part 7, adopted by IMO by Resolution MSC.61(67). On ships
linings covered by the requirements of 10.3 shall have constructed on or after 1 July 2012, the new Fire Test Procedure
a calorific value 7 not exceeding 45 MJ/m2 of the area Code, adopted by IMO by Resolution MSC.307(88), is appli-
cable.
for the thickness used. This does not apply to surfaces 9 Reference is made to the Fire Test Procedure Code, Annex 1,
of furniture fixed to linings or bulkheads as well as to Part 8, adopted by IMO by Resolution MSC.61(67). On ships
traditional wooden benches and wooden linings on constructed on or after 1 July 2012, the new Fire Test Procedure
bulkheads and ceilings in saunas. Code, adopted by IMO by Resolution MSC.307(88), is appli-
cable.
10 Reference is made to the Fire Test Procedure Code, Annex 1,
Part 9, adopted by IMO by Resolution MSC.61(67). On ships
constructed on or after 1 July 2012, the new Fire Test Procedure
6 Insulation materials used in saunas shall be of non-combustible Code, adopted by IMO by Resolution MSC.307(88), is appli-
material. cable.
7 The gross calorific value measured in accordance with ISO 11 Reference is made to the Fire Test Procedure Code, Annex 1,
standard 1716 - "Building Materials - Determination of Calo- Part 2, adopted by IMO by Resolution MSC.61(67). On ships
rific Potential", should be quoted. On ships constructed on or constructed on or after 1 July 2012, the new Fire Test Procedure
after 1 July 2012, the new Fire Test Procedure Code, adopted Code, adopted by IMO by Resolution MSC.307(88), is appli-
by IMO by Resolution MSC.307(88), is applicable. cable.
Chapter 1 Section 22 B Structural Fire Protection I - Part 1
Page 22–12 GL 2012

10.9 Primary deck coverings, if applied within 11.5.3 The traditional wooden lining on the bulk-
accommodation and service spaces and control sta- heads and on the ceiling are permitted in the sauna.
tions or if applied on cabin balconies, shall be of ap- The ceiling above the oven shall be lined with a non-
proved material which will not readily ignite, or give combustible plate with an air-gap of at least 30 mm.
rise to smoke or toxic or explosive hazards at elevated The distance from the hot surfaces to combustible
temperatures 12. materials shall be at least 500 mm or the combustible
materials shall be suitably protected.
10.10 Waste receptacles shall be constructed of
11.5.4 The traditional wooden benches are permitted
non-combustible materials with no openings in the
to be used in the sauna.
sides or bottom. Containers in galleys, pantries, bars,
garbage handling or storage spaces and incinerator 11.5.5 The sauna door shall open outwards by pushing.
rooms which are intended purely for the carriage of
wet waste, glass bottles and metal cans may be con- 11.5.6 Electrically heated ovens shall be provided
structed of combustible materials. with a timer.

11. Details of construction 12. Means of escape

11.1 In accommodation and service spaces, con- 12.1 Unless expressly provided otherwise in this
trol stations, corridors and stairways, air spaces en- regulation, at least two widely separated and ready
closed behind ceilings, panelling or linings shall be means of escape shall be provided from all spaces or
suitably divided by close-fitting draught stops not group of spaces. Lifts shall not be considered as form-
more than 14 m apart. In the vertical direction, such ing one of the required means of escape.
enclosed air spaces, including those behind linings of
stairways, trunks, etc. shall be closed at each deck. 12.2 Doors in escape routes shall, in general, open
in way of the direction of escape, except that:
11.2 The construction of ceilings and bulkheads
shall be such that it will be possible, without impairing – individual cabin doors may open into the cabins
the efficiency of the fire protection, for the fire patrols in order to avoid injury to persons in the corri-
to detect any smoke originating in concealed and inac- dor when the door is opened
cessible spaces.
– doors in vertical emergency escape trunks may
11.3 Non-load bearing partial bulkheads separat- open out of the trunk in order to permit the trunk
ing adjacent cabin balconies shall be capable of being to be used both for escape and access
opened by the crew from each side for the purpose of
fighting fires. 12.3 Stairways and ladders shall be arranged to
provide ready means of escape to the lifeboat and
11.4 The cargo holds and machinery spaces shall liferaft embarkation deck from all passenger and crew
be capable of being effectively sealed such as to pre- spaces and from spaces in which the crew is normally
vent the inlet of air. employed, other than machinery spaces. In particular,
the following provisions shall be complied with:
Doors leading to machinery spaces of category A are
to be provided with self-closing devices and 2 secur- 12.3.1 Below the bulkhead deck two means of es-
ing devices. All other machinery spaces, which are cape, at least one of which shall be independent of
protected by gas fire extinguishing system, are to be watertight doors, shall be provided from each water-
equipped with self-closing doors. tight compartment or similarly restricted space or
group of spaces. Due regard being paid to the nature
11.5 Construction and arrangement of saunas and location of spaces and to the number of persons
11.5.1 The perimeter of the sauna shall be of "A" who normally might be employed there, exceptions
class boundaries and may include changing rooms, are possible, however, stairways shall not be less than
showers and toilets. The sauna shall be insulated to "A– 800 mm in clear width with handrails on both sides.
60" standard against other spaces except those inside 12.3.2 Above the bulkhead deck, there shall be at
the perimeter and spaces of category (5), (9) and (10). least two means of escape from each main vertical
11.5.2 Bathrooms with direct access to saunas may zone or similarly restricted space or group of spaces at
be considered as part of them. In such cases, the door least one of which shall give access to a stairway
between sauna and the bathroom need not comply forming a vertical escape.
with fire safety requirements. 12.3.3 At least one of the means of escape required by
paragraphs 12.3.1 and 12.3.2 shall consist of a readily
accessible enclosed stairway, which shall provide con-
tinuous fire shelter from the level of its origin to the
12 Reference is made to the Fire Test Procedure Code, Annex 1, appropriate lifeboat and liferaft embarkation decks, or
Part 6, adopted by IMO by Resolution MSC.61(67). On ships to the uppermost weather deck if the embarkation deck
constructed on or after 1 July 2012, the new Fire Test Procedure
Code, adopted by IMO by Resolution MSC.307(88), is appli- does not extend to the main vertical zone being consid-
cable. ered. In the latter case, direct access to the embarkation
I - Part 1 Section 22 B Structural Fire Protection Chapter 1
GL 2012 Page 22–13

deck by way of external open stairways and passage- Section 14), the means of escape including stairways
ways shall be provided and shall have emergency light- and exits, shall be marked by lighting or photolumi-
ing (see also the GL Rules for Electrical Installations nescent strip indicators placed not more than 0,3 m
(I-1-3), Section 3 and 11) and slip-free surfaces under above the deck at all points of the escape route includ-
foot. Boundaries facing external open stairways and ing angles and intersections. The marking shall enable
passageways forming part of an escape route and passengers to identify all the routes of escape and
boundaries in such a position that their failure during a readily identify the escape exits. If electric illumina-
fire would impede escape to the embarkation deck shall tion is used, it shall be supplied by the emergency
have fire integrity, including insulation values, in source of power and it shall be so arranged that the
accordance with the Tables 22.1 and 22.2. The widths, failure of any single light or cut in a lighting strip, will
number and continuity of escapes shall be as follows: not result in the marking being ineffective. Addition-
ally, all escape route signs and fire equipment location
12.3.3.1 Stairways shall not be less than 900 mm in markings shall be of photoluminescent material or
clear width. Stairways shall be fitted with handrails on marked by lighting. Such lighting or photoluminescent
each side. The minimum clear width of stairways shall equipment shall be of an approved type 13.
be increased by 10 mm for every one person provided
for in excess of 90 persons. The maximum clear width 12.3.6.1 In lieu of the escape route lighting system
between handrails where stairways are wider than 900 required by paragraph 12.3.6, alternative evacuation
mm shall be 1800 mm. The total number of persons to guidance systems may be accepted if they are of ap-
be evacuated by such stairways shall be assumed to be proved type (see also the GL Rules for Electrical In-
two thirds of the crew and the total number of passen- stallations (I-1-3), Section 14) 14.
gers in the areas served by such stairways 13.
12.3.7 The requirement of 12.3.6 shall also apply to
12.3.3.2 All stairways sized for more than 90 persons the crew accommodation areas.
shall be aligned fore and aft.
12.3.8 Public Spaces spanning three or more decks
12.3.3.3 Doorways and corridors and intermediate land- and contain combustibles such as furniture and enclosed
ings included in means of escape shall be sized in the spaces such as shops, offices and restaurants shall have
same manner as stairways. The aggregate width of stair- at each level within the space two means of escape,
way exit doors to the assembly station shall not be less one of which shall have direct access to an enclosed
than the aggregate width of stairways serving this deck. vertical means of escape as mentioned under 12.3.3.
12.3.3.4 Stairways shall not exceed 3,5 m in vertical
rise without the provision of a landing and shall not 12.4 If a radiotelegraph station has no direct access
have an angle of inclination greater than 45°. to the open deck, two means of escape from or access to
such station shall be provided, one of which may be a
12.3.3.5 Landings at each deck level shall be not less porthole or window of sufficient size or another means.
than 2 m2 in area and shall increase by 1 m2 for every
10 persons provided for in excess of 20 persons but 12.5 In special category spaces the number and
need not exceed 16 m2, except for those landings ser- disposition of the means of escape both below and
vicing public spaces having direct access onto the above the bulkhead deck shall be satisfactory as men-
stairway enclosure. tioned under 12.3.1, .2 and .3.

12.3.4 Stairways serving only a space and a balcony 12.6 Two means of escape shall be provided from
in that space shall not be considered as forming one of each machinery space. In particular, the following
the means of escape. provisions shall be complied with:

12.3.5 A corridor, lobby, or part of a corridor from 12.6.1 Where the space is below the bulkhead deck
which there is only one route of escape shall not be per- the two means of escape shall consist of either:
mitted. Dead-end corridors used in service areas which 12.6.1.1 two sets of steel ladders as widely separated
are necessary for the practical utility of the ship, such as as possible, leading to doors in the upper part of the
fuel oil stations and athwartship supply corridors shall be space similarly separated and from which access is
permitted provided such dead-end corridors are sepa- provided to the appropriate lifeboat and liferaft em-
rated from crew accommodation areas and are inaccessi- barkation decks. One of these ladders shall be located
ble from passenger accommodation areas. Also, a part of within a protected enclosure having fire integrity,
the corridor that has a depth not exceeding its width is including insulation values, in accordance with the
considered a recess or local extension and is permitted. Tables 22.1 and 22.2 for a category (2) space, from the
12.3.6 In addition to the emergency lighting (see lower part of the space to a safe position outside the
also the GL Rules for Electrical Installations (I-1-3), space. Self-closing doors of the same fire integrity

14 Refer to the Functional requirements and performance standards

13 Reference is made to the Fire Safety Systems Code, adopted for the assessment of evacuation guidance systems (MSC/
by IMO by Resolution MSC.98(73). On ships constructed on or Circ. 1167) and the Interim guidelines for the testing, approval
after 1 July 2012, the new Fire Test Procedure Code, adopted and maintenance of evacuation guidance systems used as an al-
by IMO by Resolution MSC.307(88), is applicable. ternative to low-location lighting systems (MSC / Circ. 1168).
Chapter 1 Section 22 B Structural Fire Protection I - Part 1
Page 22–14 GL 2012

standards shall be fitted in the enclosure. The ladder 12.7.2 Escape routes shall be provided from every
shall be fixed in such a way that heat is not transferred normally occupied space on the ship to an assembly
into the enclosure through non-insulated fixing points. station. These escape routes shall be arranged so as to
The protected enclosure shall have minimum internal provide the most direct route possible to the assembly
dimensions of at least 800 mm × 800 mm, and shall station and shall be marked with relevant symbols.
have emergency lighting provisions.
12.7.3 Where enclosed spaces adjoin an open deck,
12.6.1.2 or one steel ladder leading to a door in the upper openings from the enclosed space to the open deck
part of the space from which access is provided to the shall, where practicable, be capable of being used as
embarkation deck and additionally, in the lower part of an emergency exit.
the space and in a position well separated from the ladder
referred to, a steel door capable of being operated from 12.7.4 Decks shall be sequentially numbered, starting
each side and which provides access to a safe escape route with "1" at the tank top or lowest deck. These numbers
from the lower part of the space to the embarkation deck. shall be prominently displayed at stair landings and lift
lobbies. Decks may also be named, but the deck num-
12.6.2 Where the space is above the bulkhead deck, ber shall always be displayed with the name.
two means of escape shall be as widely separated as
possible and the doors leading from such means of 12.7.5 Simple "mimic" plans showing the "you are
escape shall be in a position from which access is here" position and escape routes marked by arrows,
provided to the appropriate lifeboat and liferaft em- shall be prominently displayed on the inside of each
barkation decks. Where such escapes require the use cabin door and in public spaces. The plan shall show
of ladders these shall be of steel. the directions of escape, and shall be properly oriented
in relation to its position on the ship.
12.6.3 A ship of a gross tonnage less than 1 000 may
be dispensed with one of the means of escape, due 12.7.6 Cabin and stateroom doors shall not require
regard being paid to the width and disposition of the keys to unlock them from inside the room. Neither
upper part of the space; and a ship of a gross tonnage shall there be any doors along any designed escape
of 1 000 and above, may be dispensed with one means route which require keys to unlock them when moving
of escape from any such space so long as either a door in the direction of escape.
or a steel ladder provides a safe escape route to the
embarkation deck, due regard being paid to the nature 12.7.7 The lowest 0,5 m of bulkheads and other parti-
and location of the space and whether persons are tions forming vertical divisions along escape routes
normally employed in that space. shall be able to sustain a load of 750 N/m to allow
them to be used as walking surfaces from the side of
12.6.4 In the steering gear room, a second means of the escape route with the ship at large angles of heel.
escape shall be provided when the emergency steering
position is located in that space unless there is direct 12.7.8 The escape route from cabins to stairway en-
access to the open deck. closures shall be as direct as possible, with a minimum
number of changes in direction. It shall not be neces-
12.6.5 One of the escape routes from the machinery sary to cross from one side of the ship to the other to
spaces where the crew is normally employed shall reach an escape route. It shall not be necessary to climb
avoid direct access to any special category space. more than two decks up or down in order to reach an
assembly station or open deck from any passenger space.
12.6.6 Two means of escape shall be provided from
a machinery control room within a machinery space, 12.7.9 External routes shall be provided from open
at least one of which shall provide continuous fire decks, referred to in 12.7.8, to the survival craft em-
shelter to a safe position outside the machinery space. barkation stations.

12.7 Additional requirements for ro-ro passen- 12.7.10 Escape routes are to be evaluated by an
ger ships evacuation analysis early in the design process 15.
12.7.1 Handrails or other handholds shall be provided The analysis shall be used to identify and eliminate, as
in all corridors along the entire escape route, so that a far as practicable, congestion which may develop dur-
firm handhold is available every step of the way, where ing an abandonment, due to normal movement of pas-
possible, to the assembly stations and embarkation sengers and crew along escape routes, including the
stations. Such handrails shall be provided on both sides possibility that crew may need to move along these
of longitudinal corridors more than 1,8 m in width and routes in a direction opposite the movement of passen-
transverse corridors more than 1 m in width. Particular gers. In addition, the analysis shall be used to demon-
attention shall be paid to the need to be able to cross strate the escape arrangements are sufficiently flexible
lobbies, atriums and other large open spaces along es- to provide for the possibility that certain escape routes,
cape routes. Handrails and other handholds shall be of assembly stations, embarkation stations or survival
such strength as to withstand a distributed horizontal craft may not be available as a result of a casualty.
load of 750 N/m applied in the direction of the centre
of the corridor or space, and a distributed vertical load 15 Reference is made to the Interim Guidelines for evacuation
of 750 N/m applied in the downward direction. The analyses for new and existing passenger ships adopted by IMO
two loads need not be applied simultaneously. by MSC/Circ. 1238.
I - Part 1 Section 22 B Structural Fire Protection Chapter 1
GL 2012 Page 22–15

12.7.11 Designated walkways to the means of escape class standard. However, where a category 4.3 [5],
with a breadth of at least 600 mm shall be provided in 4.3 [9] or 4.3 [10] space is on one side of the division
special category and open ro-ro spaces to which any the standard may be reduced to "A-0".
passengers carried have access.
Where fuel oil tanks are below a special category
12.7.12 At least two means of escape shall be pro- space, the integrity of the deck between such spaces
vided in ro-ro spaces where the crew are normally may be reduced to "A-0" standard.
employed. The escape routes shall provide safe escape Indicators shall be provided on the navigating bridge
to the lifeboat and liferaft embarkation decks and shall which shall indicate when any fire door leading to or
be located at the fore and aft ends of the space. from the special category space is closed.
13. Fixed fire detection and fire alarm systems 14.3 Fixed fire-extinguishing system
and automatic sprinkler, fire detection and
fire alarm systems. 14.3.1 Vehicle spaces and ro-ro spaces which are
not special category spaces and are capable of being
13.1 Any ship shall be equipped with: sealed from a location outside of the cargo spaces
– an automatic sprinkler, fire detection and fire shall be fitted with a fixed gas fire-extinguishing sys-
alarm system in all service spaces, control sta- tem of an approved type (see also the GL Rules for
tions and accommodation spaces, including cor- Machinery Installations (I-1-2), Section 12).
ridors and stairways (see also the GL Rules for
Machinery Installations (I-1-2), Section 12) 14.3.2 Ro-ro and vehicle spaces not capable of being
sealed and special category spaces shall be fitted with
– a fixed fire detection and alarm system so in- a fixed pressure water spraying system for manual
stalled and arranged as to provide smoke detec- operation of an approved type (see also the GL Rules
tion in service spaces, control stations and ac- for Machinery Installations (I-1-2), Section 12).
commodation spaces, including corridors and
stairways (see also the GL Rules for Machinery 14.4 Ventilation system
Installations (I-1-2), Section 12)
There shall be provided an effective power ventilation
13.2 Control stations where water may cause dam- system for special category spaces and closed ro-ro and
age to essential equipment may be fitted with a fixed fire- vehicle spaces sufficient to give at least 10 air changes
extinguishing system of another type (see also the GL per hour. Beyond this, a higher air exchange rate is
Rules for Machinery Installations (I-1-2), Section 12). required during the period of loading and unloading.
The system for such spaces shall be entirely separated
13.3 Cabin balconies shall be equipped with a fixed from other ventilation systems and shall be operating at
fire detection and fire alarm system and a fixed pressure all times when vehicles are in such spaces.
water-spraying system (see also the GL Rules for Ma-
chinery Installations (I-1-2), Section 12), when furni- Ventilation ducts serving such spaces capable of being
ture and furnishings on such balconies are not comply- effectively sealed shall be separated for each such
ing with 10.7. space. The system shall be capable of being controlled
from a position outside such spaces.
13.4 Smoke detectors need not be fitted in private The ventilation shall be such as to prevent air stratifi-
bathrooms and galleys. Spaces having little or no fire cation and the formation of air pockets.
risk such as voids, public toilets and similar spaces
need not be fitted with an automatic sprinkler, or fixed Means shall be provided to indicate on the navigating
fire detection and alarm system. bridge any loss or reduction of the required ventilating
capacity.
14. Protection of vehicle, special category and Arrangements shall be provided to permit a rapid shut-
ro-ro spaces down and effective closure of the ventilation system in
14.1 The subdivision of such spaces in main verti- case of fire, taking into account the weather and sea
cal zones would defeat their intended purpose. There- conditions.
fore equivalent protection shall be obtained in such Ventilation ducts, including dampers, within a com-
spaces on the basis of a horizontal zone concept. A mon horizontal zone shall be made of steel.
horizontal zone may include special category and ro-
ro spaces on more than one deck provided that the Ducts passing through other horizontal zones or ma-
total overall clear height for vehicles does not exceed chinery spaces shall be "A-60" class steel ducts com-
10 m, whereas the total overall clear height is the sum plying with 9.11.1 and 9.11.2.
of distances between deck and web frames of the Permanent openings in the side plating, the ends or deck-
decks forming the horizontal zone. head of the space shall be so situated that a fire in the
cargo space does not endanger stowage areas and em-
14.2 Structural Protection
barkation stations for survival craft and accommoda-
The boundary bulkheads and decks of special category tion spaces, service spaces and control stations in su-
spaces and ro-ro spaces shall be insulated to "A-60" perstructures and deckhouses above the cargo spaces.
Chapter 1 Section 22 B Structural Fire Protection I - Part 1
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14.5 Fire detection 15.7 The floor plating of normal passageways

There shall be provided a fixed fire detection and fire shall be made of steel.
alarm system of an approved type (see also the GL
Rules for Machinery Installations (I-1-2), Section 12). 16. Special requirements for ships carrying
dangerous goods
A sample extraction smoke detection system of an
approved type (see also the GL Rules for Machinery
Installations (I-1-2), Section 12) may be accepted as 16.1 Ventilation
equivalent, except for open ro-ro spaces, open vehicle Adequate power ventilation shall be provided in en-
spaces and special category spaces. closed cargo spaces. The arrangement shall be such as
An efficient fire patrol system shall be maintained in to provide for at least six air changes per hour in the
special category spaces. In case of a continuous fire cargo space based on an empty cargo space and for
watch at all times during the voyage, a fixed fire de- removal of vapours from the upper or lower parts of
tection and alarm system is not required therein. the cargo space, as appropriate.
The fans shall be such as to avoid the possibility of
15. Special arrangements in machinery spaces ignition of flammable gas air mixtures. Suitable wire
of category A mesh guards shall be fitted over inlet and outlet venti-
lation openings.
15.1 The number of skylights, doors, ventilators,
openings in funnels to permit exhaust ventilation and 16.2 Insulation of machinery space boundaries
other openings to machinery spaces shall be reduced Bulkheads forming boundaries between cargo spaces
to a minimum consistent with the needs of ventilation and machinery spaces of category A shall be insulated
and the proper and safe working of the ship. to "A-60" standard, unless the dangerous goods are
stowed at least 3 m horizontally away from such bulk-
15.2 Skylights shall be of steel and shall not con- heads. Other boundaries between such spaces shall be
tain glass panels. Suitable arrangements shall be made insulated to "A-60" standard.
to permit the release of smoke in the event of fire,
from the space to be protected. The normal ventilation 16.3 Miscellaneous items
systems may be acceptable for this purpose.
The kind and extent of the fire extinguishing equip-
15.3 Means of control shall be provided for permit- ment are defined in the GL Rules for Machinery In-
ting the release of smoke and such controls shall be stallations (I-1-2), Section 12.
located outside the space concerned so that, in the event Electrical apparatus and cablings are to meet the re-
of fire, they will not be cut off from the space they quirements of the GL Rules for Electrical Installations
serve. The controls shall be situated at one control posi- (I-1-3), Section 16.
tion or grouped in as few positions as possible. Such
positions shall have safe access from the open deck.
17. Safety centre on passenger ships
15.4 Such doors other than power-operated water-
17.1 Application
tight doors shall be arranged so that positive closure is
assured in case of fire in the space, by power-operated Passenger ships constructed on or after 1 July 2010
closing arrangements or by the provision of self- shall have on board a safety centre complying with the
closing doors capable of closing against an inclination requirements of this regulation.
of 3,5° opposing closure and having a fail-safe hook-
back facility, provided with a remotely operated re- 17.2 Location and arrangement
lease device. Doors for emergency escape trunks need
not be fitted with a fail-safe hold-back facility and a The safety centre shall either be a part of the naviga-
remotely operated release device. tion bridge or be located in a separate space adjacent
to and having direct access to the navigation bridge, so
15.5 Means of control shall be provided for clos- that the management of emergencies can be performed
ing power-operated doors or actuating release mecha- without distracting watch officers from their naviga-
nism on doors other than power-operated watertight tional duties.
doors. The control shall be located outside the space
concerned, where they will not be cut off in the event 17.3 Layout and ergonomic design
of fire in the space it serves. The means of control The layout and ergonomic design of the safety centre
shall be situated at one control position or grouped in shall take into account the IMO guidelines 16 (com-
as few positions as possible having direct access and munication and control and monitoring of safety sys-
safe access from the open deck. tems see also the GL Rules for Electrical Installations
(I-1-3), Section 14).
15.6 Windows shall not be fitted in machinery
space boundaries. This does not preclude the use of
glass in control rooms within the machinery spaces. 16 Refer to guidelines according to MSC.1/Circ. 1368
I - Part 1 Section 22 C Structural Fire Protection Chapter 1
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C. Passenger Ships carrying not more than 36 than 1600 m2 on any deck. The length or width of a
Passengers main vertical zone is the maximum distance between
the furthermost points of the bulkheads bounding it.
1. Materials The divisions are to extend from deck to deck and to
the shell or other boundaries and shall have insulation
1.1 The hull, decks, structural bulkheads, super- values in accordance with Table 22.3. At the edges
structures and deckhouses are to be of steel or other insulating bridges are to be provided where required.
equivalent materials (aluminium alloy suitably insu-
lated). 2.2 Where a main vertical zone is subdivided by
horizontal "A" class divisions into horizontal zones for
1.2 Components made from aluminium alloys the purpose of providing an appropriate barrier be-
require special treatment, with regard to the mechani- tween sprinklered and non-sprinklered zones of the
cal properties of the material in case of temperature ship the divisions shall extend between adjacent main
increase. In principle, the following is to be observed: vertical zone bulkheads and to the shell or exterior
boundaries of the ship and shall be insulated in accor-
1.2.1 The insulation of "A" or "B" class divisions dance with the fire insulation and integrity values
shall be such that the temperature of the structural core given in Table 22.4.
does not rise more than 200 °C above the ambient
temperature at any time during the applicable fire
2.3 On ships designed for special purposes
exposure to the standard fire test. (automobile or railroad car ferries), where the provi-
sion of main vertical zone bulkheads would defeat the
1.2.2 Special attention shall be given to the insula-
purpose for which the ships is intended, equivalent
tion of aluminium alloy components of columns, stan-
means for controlling and limiting a fire are to be
chions and other structural members required to sup-
provided and specifically approved. Service spaces
port lifeboat and liferaft stowage, launching and em-
and ship stores shall not be located on ro-ro decks
barkation areas, and "A" and "B" class divisions to
unless protected in accordance with the applicable
ensure:
regulations.
that for such members supporting lifeboat and liferaft
areas and "A" class divisions, the temperature rise 3. Bulkheads within main vertical zones
limitation specified in 1.2.1 shall apply at the end of
one hour; and
3.1 All bulkheads within accommodation and
that for such members required to support "B" class service spaces which are not required to be "A" class
divisions, the temperature rise limitation specified in divisions shall be at least "B" class or "C" class divi-
1.2.1 shall apply at the end of half an hour. sions as prescribed in Table 22.3. All such divisions
may be faced with combustible materials.
1.2.3 Crowns and casings of machinery spaces of
category A shall be of steel construction and be insu- 3.2 All corridor bulkheads where not required to
lated as required by Table 22.3 as appropriate. Open- be "A" class shall be "B" class divisions which shall
ings therein, if any, shall be suitably arranged and extend from deck to deck.
protected to prevent the spread of fire.
Exceptions may be permitted when continuous "B"
class ceilings are fitted on both sides of the bulkhead
2. Main vertical zones and horizontal zones or when the accommodations are protected by an
automatic sprinkler system.
2.1 The hull, superstructure and deckhouses in
way of accommodation and service spaces are to be
3.3 All bulkheads required to be "B" class divi-
subdivided into main vertical zones the average length
sion, except corridor bulkheads prescribed in 3.2, shall
and width of which on any deck is generally not to
extend from deck to deck and to the shell or other
exceed 40 m.
boundaries unless the continuous "B" class ceilings or
Subdivision is to be effected by "A" class divisions. linings fitted on both sides of the bulkheads are at
least of the same fire resistance as the bulkhead, in
As far as practicable, the bulkheads forming the which case the bulkhead may terminate at the con-
boundaries of the main vertical zones above the bulk- tinuous ceiling or lining.
head deck shall be in line with watertight subdivision
bulkheads situated immediately below the bulkhead
deck. The length and width of main vertical zones 4. Fire integrity of bulkheads and decks
may be extended to a maximum of 48 m in order to
bring the ends of main vertical zones to coincide with 4.1 In addition to complying with the specific
subdivision watertight bulkheads or in order to ac- provisions for fire integrity of bulkheads and deck
commodate a large public space extending for the mentioned elsewhere in this Section, the minimum fire
whole length of the main vertical zone provided that integrity of all bulkheads and decks shall be as pre-
the total area of the main vertical zone is not greater scribed in Tables 22.3 to 22.4.
Chapter 1 Section 22 C Structural Fire Protection I - Part 1
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4.2 The following requirements shall govern tion for the purpose of this regulation, or where it is
application of the tables: possible to assign two or more classifications to a
space, it shall be treated as a space within the relevant
Table 22.3 shall apply to bulkheads, separating adja- category having the most stringent boundary require-
cent spaces. ments. Smaller, enclosed rooms within a space that
Table 22.4 shall apply to deck, separating adjacent have less than 30 % communicating openings to that
spaces. space are to be considered separate spaces. The fire
integrity of the boundary bulkheads of such smaller
rooms shall be as prescribed in Tables 22.3 and 22.4.
4.3 For the purpose of determining the appropri-
The title of each category is intended to be typical
ate fire integrity standards to be applied to boundaries
rather than restrictive.
between adjacent spaces, such spaces are classified
according to their fire risk as shown in the following The number in parentheses preceding each category
Categories 1 to 11. Where the contents and use of a refers to the applicable column or row number in the
space are such that there is a doubt as to its classifica- tables.

Table 22.3 Fire integrity of bulkheads separating adjacent spaces

Spaces [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11]

Control stations [1] A–03 A–0 A–60 A–0 A–15 A–60 A–15 A–60 A–60 7 A–60

Corridors [2] C5 B–05 A–01 B–05 A–60 A–0 A–0 A–15 7 A–15
B–05 A–04
Accommodation spaces [3] C5 A–01 B–05 A–60 A–0 A–0 A–15 7 A–30
B–05 A–04 A–04
Stairways [4] A–01 A–01 A–60 A–0 A–0 A–15 7 A–15
B–05 B–05 A–04 7

Service spaces (low risk) [5] C5 A–60 A–0 A–0 A–0 7 A–0

Machinery spaces of [6] 7 A–0 A–0 A–60 7 A–60

category A
Other machinery spaces [7] A–02 A–0 A–0 7 A–0
7 7
Cargo spaces [8] A–0 A–0

Service spaces (high risk) [9] A–0 7 A–30

Open decks [10] – A–0

Special category spaces and [11] A–0
ro-ro cargo spaces

Notes to be applied to Tables 22.3 and 22.4, as appropriate

1 For clarification as to which applies see 3. and 5.
2 Where spaces are of the same numerical category and superscript 2 appears, a bulkhead or deck of the ratings shown in the tables in only
required when the adjacent spaces are for a different purpose, e.g. in category 9. A galley next to a galley does not require a bulkhead but
a galley next to a paint room requires an "A–0" bulkhead.
3 Bulkheads separating the wheelhouse and chartroom from each other may be "B–0" rating. No fire rating is required for those partitions
separating the navigation bridge and the safety centre when the latter is within the navigation bridge.
4 In determining the applicable fire integrity standard of a boundary between two spaces which are protected by an automatic sprinkler
system, the lesser of the two values given in the tables shall apply.
5 For the application of 2.1, "B–0" and "C", where appearing in Table 22.3, shall be read as "A–0".
6 Fire insulation need not be fitted if the machinery space of category 7, in the opinion of the Administration, has little or no fire risk.
7 Where a 7 appears in the tables, the division is required to be of steel or other equivalent material but is not required to be of "A" class
standard.
For the application of 2.1 a 7. where appearing in Table 22.4, except for categories 8 and 10, shall be read as "A–0".
I - Part 1 Section 22 C Structural Fire Protection Chapter 1
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Table 22.4 Fire integrity of decks separating adjacent spaces

Space above
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11]
Space below
Control stations [1] A–0 A–0 A–0 A–0 A–0 A–60 A–0 A–0 A–0 7 A–30
Corridors [2] A–0 7 7 A–0 7 A–60 A–0 A–0 A–0 7 A–0

Accommodation spaces [3] A–60 A–0 7 A–0 7 A–60 A–0 A–0 A–0 7 A–30
A–0 4
Stairways [4] A–0 A–0 A–0 7 A–0 A–60 A–0 A–0 A–0 7 A–0
Service spaces (low risk) [5] A–15 A–0 A–0 A–0 7 A–60 A–0 A–0 A–0 7 A–0
machinery spaces of [6] A–60 A–60 A–60 A–60 A–60 7 A–60 6 A–30 A–60 7 A–60
category A
Other machinery spaces [7] A–15 A–0 A–0 A–0 A–0 A–0 7 A–0 A–0 7 A–0
Cargo spaces [8] A–60 A–0 A–0 A–0 A–0 A–0 A–0 7 A–0 7 A–0

Service spaces [9] A–60 A–30 A–30 A–30 A–0 A–60 A–0 A–0 A–0 7 A–30
(high risk) A–0 4 A–04 A–04
Open decks [10] 7 7 7 7 7 7 7 7 7 – A–0

Special category spaces [11] A–60 A–15 A–30 A–15 A–0 A–30 A–0 A–0 A–30 A–0 A–0
and ro-ro cargo spaces A–0 4

See notes under Table 22.3.

[1] Control stations [6] Machinery spaces of category A

Spaces containing emergency sources of power Spaces and trunks to such spaces which contain:
and lighting. Wheelhouse and chartroom. Spaces internal combustion machinery used for main
containing the ship's radio equipment. Fire con- propulsion; or
trol stations. Control room for propulsion ma-
chinery when located outside the propulsion ma- internal combustion machinery used for pur-
chinery space. Spaces containing centralized fire poses other than main propulsion where such
alarm equipment. machinery has in the aggregate a total power
output of not less than 375 kW; or
[2] Corridors
any oil-fired boiler or oil fuel unit.
Passenger and crew corridors and lobbies.
[7] Other machinery spaces
[3] Accommodation spaces
Spaces, other than machinery spaces of category
Spaces used for public spaces, lavatories, cab- A, containing propulsion machinery, boilers, oil
ins, offices, hospitals, cinemas, games and hob- fuel units, steam and internal combustion en-
by rooms, barber shops, pantries containing no gines, generators and major electrical machinery,
cooking appliances and similar spaces. oil filling stations, refrigerating, stabilizing, ven-
[4] Stairways tilation and air conditioning machinery, and
similar spaces, and trunks to such spaces.
Interior stairways, lifts, totally enclosed emer- Electrical equipment rooms (auto-telephone ex-
gency escape trunks and escalators (other than change, air-conditioning duct spaces)
those wholly contained within the machinery
spaces) and enclosures thereto. [8] Cargo spaces
In this connection, a stairway which is enclosed All spaces used for cargo (including cargo oil
only at one level shall be regarded as part of the tanks) and trunkways and hatchways to such
space from which it is not separated by a fire door. spaces, other than special category spaces.
[5] Service spaces (low risk) [9] Service spaces (high risk)
Lockers and store-rooms not having provisions for Galleys, pantries containing cooking appliances,
the storage of flammable liquids and having are- paint and lamp rooms, lockers and store-rooms
as less than 4 m2 and drying rooms and laundries. having areas of 4 m2 or more, spaces for the stor-
Chapter 1 Section 22 C Structural Fire Protection I - Part 1
Page 22–20 GL 2012

age of flammable liquids, saunas and workshops spaces may also have direct access to stairways enclo-
other than those forming part of the machinery sures except for the backstage of a theatre. Small cor-
spaces. ridors or lobbies used to separate an enclosed stairway
from galleys or main laundries may have direct access
[10] Open decks to the stairway provided they have a minimum deck
Open deck spaces and enclosed promenades area of 4,5 m2, a width of no less than 900 mm and
having little or no fire risk. Enclosed promenades contain a fire hose station.
shall have no significant fire risk, meaning that
5.3 Lift trunks shall be so fitted as to prevent the
furnishing should be restricted to deck furniture.
passage of smoke and flame from one 'tween deck to
In addition, such spaces shall be naturally venti-
another and shall be provided with means of closing
lated by permanent openings. Air spaces (the
so as to permit the control of draught and smoke.
space outside superstructure and deckhouses).
[11] Special category spaces and ro-ro cargo spaces 6. Openings in "A" class divisions

4.4 Continuous "B" class ceilings or linings, in 6.1 Where "A" class divisions are penetrated for the
association with the relevant decks or bulkheads, may passage of electric cables, pipes, trunks, ducts, etc., or
be accepted as contributing wholly or in part, to the for girders, beams or other structural members, arrange-
required insulation and integrity of a division. ments shall be made to ensure that the fire resistance
is not impaired, subject to the provisions of 6.7.
4.5 See B.4.5.
6.2 All openings in the divisions are to be provided
4.6 Protection of atriums with permanently attached means of closing which
shall be at least as effective for resisting fire as the
4.6.1 Atriums shall be within enclosures formed of divisions 3. This does not apply for hatches between
"A" class divisions having a fire rating determined in cargo, special category, store and baggage spaces and
accordance with Table 22.4, as applicable. between such spaces and the weather decks.

4.6.2 Decks separating spaces within atriums shall 6.3 The construction of all doors and door frames
have a fire rating determined in accordance with Table in "A" class divisions, with the means of securing
22.4, as applicable. them when closed, shall provide resistance to fire as
well as to the passage of smoke and flame, equivalent
5. Protection of stairways and lifts in ac- to that of the bulkheads in which the doors are situ-
commodation and service spaces ated 3. Such doors and door frames shall be approved
by GL and constructed of steel or other equivalent
5.1 All stairways in accommodation and service material. Doors approved without the sill being part of
spaces are to be of steel frame or other approved the frame, which are installed on or after 1 July 2010,
equivalent construction; they are to be arranged within shall be installed such that the gap under the door does
enclosures formed by "A" Class divisions, with effec- not exceed 12 mm. A non-combustible sill shall be
tive means of closure for all openings. installed under the door such that floor coverings do
not extend beneath the closed door.
The following exceptions are admissible:
6.4 Watertight doors need not be insulated.
5.1.1 A stairway connecting only two decks need not
be enclosed, provided that the integrity of the pierced 6.5 It shall be possible for each door to be opened
deck is maintained by suitable bulkheads or doors at and closed from each side of the bulkhead by one
one of the two decks. When a stairway is closed at one person only.
'tween deck space, the stairway enclosed shall be
protected in accordance with the tables for decks. 6.6 Fire doors in main vertical zone bulkheads, gal-
ley boundaries and stairway enclosures other than power-
5.1.2 Stairways fitted within a closed public space
operated watertight doors and those which are normally
need not be enclosed.
locked, shall satisfy the following requirements:
5.2 Stairway enclosures are to be directly acces- 6.6.1 The doors shall be self-closing and be capa-
sible from the corridors and of sufficient area to pre- ble of closing against an angle of inclination of up to
vent congestion, having in mind the number of per- 3,5° opposing closure.
sons likely to use them in an emergency. Within the
perimeter of such stairway enclosures, only public 6.6.2 The approximate time of closure for hinged
spaces, lockers of non-combustible material providing fire doors shall be no more than 40 s and no less than
storage for safety equipment and open information 10 s from the beginning of their movement with the
counters are permitted. Only corridors, public toilets, ship in upright position. The approximate uniform rate
special category spaces, other escape stairways re- of closure for sliding fire doors shall be of no more
quired by 12.3.3 and external areas are permitted to than 0,2 m/s and no less than 0,1 m/s with the ship in
have direct access to these stairway enclosures. Public the upright position.
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6.6.3 The doors, except those for emergency es- able to operate in case of fire 3. This system shall
cape trunks shall be capable of remote release from satisfy the following requirements:
the continuously manned central control station, either
simultaneously or in groups and shall be capable of 6.6.15.1 the control system shall be able to operate
release also individually from a position at both sides the door at the temperature of at least 200 °C for at
of the door. Release switches shall have an on-off least 60 min, served by the power supply;
function to prevent automatic resetting of the system.
6.6.15.2 the power supply for all other doors not sub-
6.6.4 Hold-back hooks not subject to central con- ject to fire shall nor be impaired; and
trol station release are prohibited.
6.6.15.3 at temperatures exceeding 200 °C the control
6.6.5 A door closed remotely from the central con- system shall be automatically isolated from the power
trol station shall be capable of being re-opened at both supply and shall be capable of keeping the door closed
sides of the door by local control. After such local up to at least 945 °C.
opening, the door shall automatically close again (see
also the GL Rules for Electrical Installations (I-1-3), 6.7 Where a space is protected by an automatic
Section 9). sprinkler system or fitted with a continuous "B" class
ceiling, openings in decks not forming steps in main
6.6.6 Indication shall be provided at the fire door vertical zones nor bounding horizontal zones shall be
indicator panel in the continuously manned central closed reasonably tight and such decks shall meet the
control station whether each of the remote-released "A" class integrity requirements in so far as is reason-
doors are closed. able and practicable.
6.6.7 The release mechanism shall be so designed 6.8 The requirements for "A" class integrity of the
that the door will automatically close in the event of outer boundaries of a ship shall not apply to glass parti-
disruption of the control system or main source of tions, windows and sidescuttles, provided that there is
electric power. no requirement for such boundaries to have "A" class
integrity in 8.3. The requirements for "A" class integ-
6.6.8 Local power accumulators for power-
rity of the outer boundaries of the ship shall not apply
operated doors shall be provided in the immediate
to exterior doors, except for those in superstructures
vicinity of the doors to enable the doors to be operated
and deckhouses facing life-saving appliances, embar-
after disruption of the control system or main source
kation and external muster station areas, external stairs
of electric power at least ten times (fully opened and
and open decks used for escape routes. Stairway en-
closed) using the local controls (see also the GL Rules
closure doors need not meet this requirement.
for Machinery Installations (I-1-2), Section 14).
6.6.9 Disruption of the control system or main 6.9 Except for watertight, weathertight doors (semi-
source of electric power at one door shall not impair watertight doors), doors leading to the open deck and
the safe functioning of the other doors. doors which need reasonably gastight, all "A" class
doors located in stairways, public spaces and main verti-
6.6.10 Remote-released sliding or power-operated cal zone bulkheads in escape routes shall be equipped
doors shall be equipped with an alarm that sounds for with a self-closing hose port of material, construction
at least 5 s but no more than 10 s after the door is and fire resistance which is equivalent to the door into
released from the central control station and before the which it is fitted, and shall be a 150 mm square clear
door begins to move and continue sounding until the opening with the door closed and shall be inset into
door is completely closed. the lower edge of the door, opposite the door hinges,
or in the case of sliding doors, nearest the opening.
6.6.11 A door designed to re-open upon contacting
an object in its path shall re-open not more than 1 m 7. Openings in "B" class divisions
from the point of contact.
7.1 Where "B" class divisions are penetrated for
6.6.12 Double-leaf doors equipped with a latch
the passage of electric cables, pipes, trunks, ducts,
necessary to their fire integrity shall have a latch that
etc., or for the fitting of ventilation terminals, lighting
is automatically activated by the operation of the
fixtures and similar devices, arrangements shall be
doors when released by the control system.
made to ensure that the fire resistance is not impaired.
6.6.13 Doors giving direct access to special category See also B.7.1.
spaces which are power-operated and automatically 7.2 Doors and door frames in "B" class divisions
closed need not be equipped with the alarms and re- and means of securing them shall provide a method of
mote-release mechanisms required in 6.6.3 and 6.6.10. closure which shall have resistance to fire equivalent
6.6.14 The components of the local control system to that of the divisions 3 except that ventilation open-
shall be accessible for maintenance and adjusting. ings may be permitted in the lower portion of such doors.
Doors approved as "A" class without the sill being part
6.6.15 Power-operated doors shall be provided with of the frame, which are installed on or after 1 July 2010,
a control system of an approved type which shall be shall be installed such that the gap under the door does
Chapter 1 Section 22 C Structural Fire Protection I - Part 1
Page 22–22 GL 2012

not exceed 12 mm and a non-combustible sill shall be 9. Ventilation systems

installed under the door such that floor coverings do
not extend beneath the closed door. Doors approved as 9.1 Ventilation ducts shall be of steel or equiva-
"B" class without the sill being part of the frame, lent material. Short ducts, however, not generally
which are installed on or after 1 July 2010, shall be exceeding 2 m in length and with a cross-section not
installed such that the gap under the door does not ex- exceeding 0,02 m2 need not be steel or equivalent,
ceed 25 mm. Where such opening is in or under a door subject to the following conditions:
the total net area of any such opening or openings shall
not exceed 0,05 m2. Alternatively, a non-combustible 9.1.1 subject to 9.1.2 these ducts shall be of any
air balance duct between the cabin and the corridor, material having low flame spread characteristics 4
and located below the sanitary unit is permitted where which is type approved;
the cross-sectional area of the duct does not exceed
9.1.2 on ships constructed on or after 1 July 2010,
0,05 m2. All ventilation openings shall be fitted with a
the ducts shall be made of heat resisting non-com-
grill made of non-combustible material. Doors shall be
bustible material, which may be faced internally and
non-combustible and approved by GL.
externally with membranes having low flame-spread
7.3 Cabin doors in "B" class division shall be of a characteristics and, in each case, a calorific value 5 not
self closing type. Hold-backs are not permitted. exceeding 45 MJ/m2 of their surface area for the
thickness used;
7.4 The requirements for "B" class integrity of
the outer boundaries of a ship shall not apply to glass 9.1.3 they may only be used at the end of the venti-
partitions, windows and sidescuttles. Similarly, the lation device;
requirements for "B" class integrity shall not apply to 9.1.4 they shall not be situated less than 600 mm,
exterior doors in superstructures and deckhouses. measured along the duct, from an opening in an "A" or
7.5 Where an automatic sprinkler system is fitted: "B" class division including continuous "B" class
ceilings.
7.5.1 openings in decks not forming steps in main
vertical zones nor bounding horizontal zones shall be 9.2 Where a thin plated duct with a free cross-
closed reasonably tight and such decks shall meet the sectional area equal to or less than 0,02 m2 pass
"B" class integrity requirements in so far as is reason- through "A" class bulkheads or decks, the opening
able and practicable and shall be lined with a steel sheet sleeve having a thick-
ness of at least 3 mm and a length of at least 200 mm,
7.5.2 openings in corridor bulkheads of "B" class divided preferably into 100 mm on each side of the
materials shall be protected in accordance with the bulkhead or, in the case of the deck, wholly laid on the
provisions of 3.2. lower side of the decks pierced.
Where ventilation ducts with a free cross-sectional
8. Windows and sidescuttles area exceeding 0,02 m2 pass through "A" class bulk-
heads or decks, the opening shall be lined with a steel
8.1 All windows and sidescuttles in bulkheads sheet sleeve. However, where such ducts are of steel
within accommodation and service spaces and control construction and pass through a deck or bulkhead, the
stations other than those to which the provisions of 6.8 ducts and sleeves shall comply with the following:
and of 7.4 apply, shall be so constructed as to preserve
the integrity requirements of the type of bulkheads in 9.2.1 The sleeves shall have a thickness of at least
which they are fitted. 3 mm and a length of at least 900 mm. When passing
through bulkheads, this length shall be divided pref-
8.2 Notwithstanding the requirements of the Ta- erably into 450 mm on each side of the bulkhead.
bles 22.3 and 22.4 all windows and sidescuttles in bulk- These ducts, or sleeves lining such ducts, shall be
heads separating accommodation and service spaces provided with fire insulation. The insulation shall have
and control stations from weather shall be constructed at least the same fire integrity as the bulkhead or deck
with frames of steel or other suitable material. The through which the duct passes.
glass shall be retained by a metal glazing bead or angle.
9.2.2 Ducts with a free cross-sectional area exceed-
8.3 Windows facing life-saving appliances, embar- ing 0,075 m2 shall be fitted with fire dampers in addi-
kation and muster areas, external stairs and open decks tion to the requirements of 9.2.1. The fire damper shall
used for escape routes, and windows situated below operate automatically but shall also be capable of being
liferaft and escape slide embarkation areas shall have closed manually from both sides of the bulkhead or
the fire integrity as required in the Tables 22.1 and 22.2. deck. The damper shall be provided with an indicator
Where automatic dedicated sprinkler heads are pro- which shows whether the damper is open or closed.
vided for windows (see also the GL Rules for Machin- Fire dampers are not required, however, where ducts
ery Installations (I-1-2), Section 12), A-0 windows may pass through spaces surrounded by "A" class division,
be accepted as equivalent. Windows located in the without serving those spaces, provided those ducts
ship's side below the lifeboat embarkation areas shall have the same fire integrity as the divisions which they
have the fire integrity at least equal to "A-0" class. pierce. The fire dampers should be easily accessible.
I - Part 1 Section 22 C Structural Fire Protection Chapter 1
GL 2012 Page 22–23

Where they are placed behind ceilings and linings, these automatic fire damper shall be fitted in the galley
latter should be provided with an inspection door on ventilation duct near the ventilation unit.
which a plate reporting the identification number of the
fire damper. Such plate and identification number should 9.7 Ducts provided for the ventilation of machin-
be placed also on any remote control required. ery spaces of category A, galleys, vehicle spaces, ro-ro
cargo spaces or special category spaces shall not pass
9.2.3 The following arrangement shall be of an through accommodation spaces, service spaces or
approved type 3: control stations unless the ducts are either complying
with 9.7.1 or 9.7.2:
– fire dampers, including relevant means of opera-
tion 9.7.1 constructed of steel having a thickness of at
least 3 mm and 5 mm for ducts the widths or diame-
– duct penetrations through "A" class divisions. ters of which are up to and including 300 mm and
Where steel sleeves are directly joined to venti-
760 mm and over respectively and, in the case of such
lation ducts by means of riveted or screwed ducts, the widths or diameters of which are between
flanges or by welding, the test is not required. 300 mm and 760 mm having a thickness to be ob-
tained by interpolation;
9.3 The main inlets and outlets of all ventilation
systems shall be capable of being closed from outside suitably supported and stiffened;
the respective spaces in the event of a fire. fitted with automatic fire dampers close to the bounda-
ries penetrated; and
9.4 Where they pass through accommodation
spaces or spaces containing combustible materials, the insulated to "A-60" standard from the machinery
exhaust ducts from galley ranges shall be constructed spaces, galleys, vehicle spaces, ro-ro cargo spaces or
of insulated "A" class divisions. Each exhaust duct special category spaces to a point at least 5 m beyond
shall be fitted with: each fire damper; or
– a grease trap readily removable for cleaning; 9.7.2 constructed of steel suitable supported and
stiffened in accordance with 9.7.1 and
– a fire damper located in the lower end of the
duct and in addition, a fire damper in the upper insulated to "A-60" standard throughout the accom-
end of the duct; modation spaces, service spaces or control stations;
– arrangements, operable from within the galley, except that penetrations of main zone divisions shall
for shutting off the exhaust fan; and also comply with the requirements of 9.11.
– fixed means for extinguishing a fire within the 9.8 Ducts provided for the ventilation to accom-
duct (see the GL Rules for Machinery Installa- modation spaces, service spaces or control stations
tions (I-1-2), Section 12). shall not pass through machinery spaces of category
A, galleys, vehicle spaces, ro-ro cargo spaces or spe-
9.5 Such measures as are practicable shall be cial category spaces unless either complying with
taken in respect of control stations outside machinery 9.8.1 or 9.8.2.
spaces in order to ensure that ventilation, visibility and
freedom from smoke are maintained, so that in the 9.8.1 the ducts where they pass through a machin-
event of fire the machinery and equipment contained ery space of category A, galley, vehicle space, ro-ro
therein may be supervised and continue to function cargo space or special category space are constructed
effectively. Alternative and separate means of air of steel, suitable supported and stiffened in accordance
supply shall be provided; air inlets of the two sources with 9.7.1 and
of supply shall be so disposed that the risk of both automatic fire dampers are fitted close to the bounda-
inlets drawing in smoke simultaneously is minimized. ries penetrated; and
Such requirements need not apply to control stations
situated on, and opening on to, an open deck. integrity of the machinery space, galley, vehicle space,
ro-ro cargo space or special category space boundaries
The ventilation system serving safety centres may be is maintained at the penetrations; or
derived from the ventilation system serving the navi-
gation bridge, unless located in an adjacent main ver- 9.8.2 the ducts where they pass through a machin-
tical zone. ery space of category A, galley, vehicle space, ro-ro
cargo space or special category space are constructed
9.6 The ventilation systems for machinery spaces of steel, suitable supported and stiffened in accordance
of category A, vehicle spaces, ro-ro spaces, galleys, with 9.7.1 and
special category spaces and cargo spaces shall, in
are insulated to "A-60" standard within the machinery
general, be separated from each other and from the
space, galley, vehicle space, ro-ro cargo space or spe-
ventilation system serving other spaces. Except, that
cial category space;
the galley ventilation systems need not be completely
separated, but may be served by separate ducts from a except that penetrations of main zone division shall
ventilation unit serving other spaces. In any case, an also comply with the requirements of 9.11.
Chapter 1 Section 22 C Structural Fire Protection I - Part 1
Page 22–24 GL 2012

9.9 Ventilation ducts with a free cross-sectional area 10.4 The total volume of combustible facings,
exceeding 0,02 m2 passing through "B" class bulkheads mouldings, decorations and veneers in any accommo-
shall be lined with steel sheet sleeves of 900 mm in dation and service space shall not exceed a volume
length divided preferably into 450 mm on each side of equivalent to 2,5 mm veneer on the combined area of
the bulkheads unless the duct is of steel for this length. the walls and ceilings. Furniture fixed to linings, bulk-
heads or decks need not be included in the calculation
9.10 Power ventilation of accommodation spaces, of the total volume of combustible materials. This
service spaces, cargo spaces, control stations and ma- applies also to traditional wooden benches and
chinery spaces shall be capable of being stopped from wooden linings on bulkheads and ceilings in saunas.
an easily accessible position outside the space being In the case of ships fitted with an automatic sprinkler
served. This position should not be readily cut off in system, the above volume may include some combus-
the event of a fire in the spaces served. The means pro- tible material used for erection of "C" class divisions.
vided for stopping the power ventilation of the machin-
ery spaces shall be entirely separate from the means 10.5 Combustible materials used on surfaces and
provided for stopping ventilation of other spaces. linings covered by the requirements of 10.3 shall have
a calorific value 17 not exceeding 45 MJ/m2 of the
9.11 Where in a passenger ship it is necessary that area for the thickness used. This does not apply to
a ventilation duct passes through a main vertical zone surfaces of furniture fixed to linings or bulkheads as
division, a fail-safe automatic closing fire damper well as to traditional wooden benches and wooden
shall be fitted adjacent to the division. The damper linings on bulkheads and ceilings in saunas.
shall also be capable of being manually closed from
each side of the division. The operating position shall 10.6 Furniture in stairway enclosures shall be
be readily accessible and be marked in red light- limited to seating. It shall be fixed, limited to six seats
reflecting colour. The duct between the division and on each deck in each stairway enclosure, be of re-
the damper shall be of steel or other equivalent mate- stricted fire risk, and shall not restrict the passenger
rial and, if necessary, insulated to comply with the escape route.
requirements of 6.1. The damper shall be fitted on at
least one side of the division with a visible indicator Furniture shall not be permitted in passenger and crew
showing whether the damper is in the open position. corridors forming escape routes in cabin areas. Lock-
ers of non-combustible material, providing storage for
10. Restriction of combustible materials safety equipment, may be permitted within these areas.
Drinking water dispensers and ice cube machines may
10.1 Except in cargo spaces, mail rooms, baggage be permitted in corridors provided they are fixed and
rooms, saunas 6 or refrigerated compartments of ser- do not restrict the width of the escape route. This
vice spaces, all linings, grounds, draughts stops, ceil- applies as well to decorative flower arrangements,
ings and insulation's shall be of non-combustible ma- statues or other objects d'art such as paintings and
terials 3. Partial bulkheads or decks used to subdivide tapestries in corridors and stairways.
a space for utility or artistic treatment shall also be of
non-combustible material. 10.7 Furniture and furnishings on cabin balconies
Linings, ceilings and partial bulkheads or decks used shall comply with the following, unless such balconies
to screen or to separate adjacent cabin balconies shall are protected by a fixed pressure water-spraying and
be of non-combustible material. fixed fire detection and fire alarm systems (see B.10.7).

10.2 Vapour barriers and adhesives used in con- 10.8 Paints, varnishes and other finishes used on
junction with insulation, as well as insulation of pipe exposed interior surfaces, including cabin balconies
fittings, for cold service systems need not be non- with the exclusion of natural hard wood decking sys-
combustible but they shall be kept to the minimum tems, shall not be capable of producing excessive
quantity practicable and their exposed surfaces shall quantities of smoke and toxic products 11.
have low flame spread characteristics.
10.9 Primary deck coverings, if applied within
10.3 The following surfaces shall have low flame- accommodation and service spaces and control sta-
spread characteristics 4: tions, or if applied on cabin balconies, shall be of
approved material which will not readily ignite, or
10.3.1 exposed surfaces in corridors and stairway give rise to smoke or toxic or explosive hazards at
enclosures, and of bulkheads, wall and ceiling linings elevated temperatures 12.
in all accommodation and service spaces (except sau-
nas) and control stations; 10.10 Waste receptacles (see B.10.10).

10.3.2 concealed or inaccessible spaces in accom-

modation, service spaces and control stations,
17 The gross calorific value measured in accordance with ISO
10.3.3 exposed surfaces of cabin balconies, except standard 1716 - "Building materials - Determination of Calo-
for natural hard wood decking systems. rific Potential", should be quoted.
I - Part 1 Section 22 C Structural Fire Protection Chapter 1
GL 2012 Page 22–25

11. Details of construction 12.3.1 Below the bulkhead deck, two means of es-
cape, at least one of which shall be independent of
11.1 In accommodation and service spaces, con- watertight doors, shall be provided from each water-
trol stations, corridors and stairways: tight compartment or similarly restricted space or
group of spaces. Due regard being paid to the nature
air spaces enclosed behind ceilings, panelling or lin- and location of spaces and to the number of persons
ings shall be suitably divided by close-fitting draught who normally might be employed there, exceptions
stops not more than 14 m apart; are possible, however, stairways shall not be less than
in the vertical direction, such enclosed air spaces, 800 mm in clear width with handrails on both sides.
including those behind linings of stairways, trunks, 12.3.2 Above the bulkhead deck, there shall be at
etc. shall be closed at each deck. least two means of escape from each main vertical
zone or similarly restricted space or group of spaces at
11.2 The construction of ceilings and bulkheads least one of which shall give access to a stairway
shall be such that it will be possible, without impairing forming a vertical escape.
the efficiency of the fire protection, for the fire patrols
to detect any smoke originating in concealed and inac- 12.3.3 At least one of the means of escape required
cessible spaces. by paragraphs 12.3.1 and 12.3.2 shall consist of a
readily accessible enclosed stairway, which shall pro-
11.3 Non-load bearing partial bulkheads separat- vide continuous fire shelter from the level of its origin
ing adjacent cabin balconies shall be capable of being to the appropriate lifeboat and liferaft embarkation
opened by the crew from each side for the purpose of decks, or to the uppermost weather deck if the em-
fighting fires. barkation deck does not extend to the main vertical
zone being considered. In the latter case, direct access
11.4 The cargo holds and machinery spaces shall to the embarkation deck by way of external open stair-
be capable of being effectively sealed such as to pre- ways and passageways shall be provided and shall
vent the inlet of air. have emergency lighting (see also the GL Rules for
Electrical Installations (I-1-3), Section 3 and 11) and
Doors leading to machinery spaces of group A are to slip-free surfaces under foot. Boundaries facing exter-
be provided with self-closing devices and 2 securing nal open stairways and passageways forming part of
devices. All other machinery spaces, which are pro- an escape route and boundaries in such a position that
tected by a gas fire extinguishing system, are to be their failure during a fire would impede escape to the
equipped with self-closing doors. embarkation deck shall have fire integrity, including
insulation values, in accordance with the Tables 22.3
11.5 Construction and arrangement of saunas (see and 22.4. The widths, number and continuity of es-
B.11.5). capes shall be as follows:
12.3.3.1 Stairways shall not be less than 900 mm in
12. Means of escape clear width. Stairways shall be fitted with handrails on
each side. The minimum clear width of stairways shall
12.1 Unless expressly provided otherwise in this be increased by 10 mm for every one person provided
regulation, at least two widely separated and ready for in excess of 90 persons. The maximum clear width
means of escape shall be provided from all spaces or between handrails where stairways are wider than
group of spaces. Lifts shall not be considered as form- 900 mm shall be 1 800 mm. The total number of persons
ing one of the required means of escape. to be evacuated by such stairways shall be assumed to
be two thirds of the crew and the total number of pas-
12.2 Doors in escape routes shall, in general, open sengers in the areas served by such stairways 13.
in-way of the direction of escape, except that 12.3.3.2 All stairways sized for more than 90 persons
shall be aligned fore and aft.
12.2.1 individual cabin doors may open into the
cabins in order to avoid injury to persons in the corri- 12.3.3.3 Doorways and corridors and intermediate
dor when the door is opened, and landings included in means of escape shall be sized in
the same manner as stairways.
12.2.2 doors in vertical emergency escape trunks
may open out of the trunk in order to permit the trunk 12.3.3.4 Stairways shall not exceed 3,5 m in vertical
to be used both for escape and access. rise without the provision of a landing and shall not
have an angle of inclination greater than 45°.
12.3 Stairways and ladders shall be arranged to 12.3.3.5 Landings at each deck level shall be not less
provide ready means of escape to the lifeboat and than 2 m2 in area and shall increase by 1 m2 for every
liferaft embarkation deck from all passenger and crew 10 persons provided for in excess of 20 persons but
spaces and from spaces in which the crew is normally need not exceed 16 m2, except for those landings ser-
employed, other than machinery spaces. In particular, vicing public spaces having direct access onto the
the following provisions shall be complied with: stairway enclosure.
Chapter 1 Section 22 C Structural Fire Protection I - Part 1
Page 22–26 GL 2012

12.3.4 Stairways serving only a space and a balcony 12.6.1.1 two sets of steel ladders as widely separated
in that space shall not be considered as forming one of as possible, leading to doors in the upper part of the
the means of escape. space similarly separated and from which access is
provided to the appropriate lifeboat and liferaft em-
12.3.5 A corridor, lobby, or part of a corridor from barkation decks. One of these ladders shall be located
which there is only one route of escape shall be pro- within a protected enclosure having fire integrity,
hibited. Dead-end corridors used in service areas including insulation values, in accordance with the
which are necessary for the practical utility of the Tables 22.3 and 22.4 for a category (4) space, from the
ship, such as fuel oil stations and athwartship supply lower part of the space to a safe position outside the
corridors shall be permitted provided such dead-end space. Self-closing doors of the same fire integrity
corridors are separated from crew accommodation standards shall be fitted in the enclosure. The ladder
areas and are inaccessible from passenger accommo- shall be fixed in such a way that heat is not transferred
dation areas. Also, a part of the corridor that has a into the enclosure through non-insulated fixing points.
depth not exceeding its width is considered a recess or The protected enclosure shall have minimum internal
local extension and is permitted. dimensions of at least 800 mm × 800 mm, and shall
have emergency lighting provisions.
12.3.6 In addition to the emergency lighting (see
also the GL Rules for Electrical Installations (I-1-3), 12.6.1.2 or one steel ladder leading to a door in the
Section 14) the means of escape including stairways upper part of the space from which access is provided
and exits, shall be marked by lighting or photolumi- to the embarkation deck an additionally, in the lower
nescent strip indicators placed not more than 0,3 m part of the space and in a position well separated from
above the deck at all points of the escape route includ- the ladder referred to, a steel door capable of being
ing angles and intersections. The marking shall enable operated from each side and which provides access to
passengers to identify all the routes of escape and a safe escape route from the lower part of the space to
readily identify the escape exits. If electric illumina- the embarkation deck.
tion is used, it shall be supplied by the emergency
source of power and it shall be so arranged that the 12.6.2 Where the space is above the bulkhead deck,
failure of any single light or cut in a lighting strip, will two means of escape shall be as widely separated as
not result in the marking being ineffective. Addition- possible and the doors leading from such means of
ally, all escape route signs and fire equipment location escape shall be in a position from which access is
markings shall be of photoluminescent material or provided to the appropriate lifeboat and liferaft em-
marked by lighting. Such lighting or photoluminescent barkation decks. Where such escapes require the use
equipment shall be of an approved type 13. of ladders these shall be of steel.
12.3.6.1 In lieu of the escape route lighting system
12.6.3 A ship of a gross tonnage less than 1 000 may
required by paragraph 12.3.6, alternative evacuation
be dispensed with one of the means of escape, due
guidance systems may be accepted if they are of ap-
regard being paid to the width and disposition of the
proved type (see also the GL Rules for Electrical In-
upper part of the space; and a ship of a gross tonnage
stallations (I-1-3), Section 14) 14. of 1 000 and above, may be dispensed with one means
of escape from any such space so long as either a door
12.3.7 Public Spaces spanning three or more decks or a steel ladder provides a safe escape route to the
and contain combustibles such as furniture and enclosed embarkation deck, due regard being paid to the nature
spaces such as ships, offices and restaurants shall have at and location of the space and whether persons are
each level within the space two means of escape, one normally employed in that space.
of which shall have direct access to an enclosed verti-
cal means of escape as mentioned under 12.3.3. 12.6.4 In the steering gear room, a second means of
escape shall be provided when the emergency steering
12.4 If a radiotelegraph station has no direct access position is located in that space unless there is direct
to the open deck, two means of escape from or access to access to the open deck.
such station shall be provided, one of which may be a
porthole or window of sufficient size or another means. 12.6.5 One of the escape routes from the machinery
spaces where the crew is normally employed shall
12.5 In special category spaces the number and avoid direct access to any special category space.
disposition of the means of escape both below and
above the bulkhead deck shall be satisfactory as men- 12.6.6 Two means of escape shall be provided from
tioned under 12.3.1, .2 and .3. a machinery control room within a machinery space,
at least one of which shall provide continuous fire
12.6 Two means of escape shall be provided from shelter to a safe position outside the machinery space.
each machinery space. In particular, the following
provisions shall be complied with: 12.7 Additional requirements for ro-ro passen-
ger ships
12.6.1 Where the space is below the bulkhead deck
the two means of escape shall consist of either: See B.12.7.
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GL 2012 Page 22–27

13. Fixed fire detection and fire alarm systems 14.4 Ventilation system
and automatic sprinkler, fire detection and
There shall be provided an effective power ventilation
fire alarm systems
system for special category spaces sufficient to give at
In any ship there shall be installed throughout each least 10 air changes per hour and for closed ro-ro and
separate zone, whether vertical or horizontal, in all vehicle spaces sufficient to give at least 6 air changes
accommodation and service spaces and, where it is per hour. Beyond this, a higher air exchange rate is
considered necessary, in control stations, except required during the period of loading and unloading.
spaces which afford no substantial fire risk (such as The system for such spaces shall be entirely separated
void spaces, sanitary spaces, etc.) either: from other ventilation systems and shall be operating
at all times when vehicles are in such spaces.
13.1 a fixed fire detection and fire alarm system Ventilation ducts serving such spaces capable of being
(see also the GL Rules for Machinery Installations (I- effectively sealed shall be separated for each such
1-2), Section 12); or space. The system shall be capable of being controlled
from a position outside such spaces.
13.2 an automatic sprinkler, fire detection and fire
alarm system and in addition a fixed fire detection and The ventilation shall be such as to prevent air stratifi-
fire alarm system so installed and arranged as to pro- cation and the formation of air pockets.
vide smoke detection in corridors, stairways and es- Means shall be provided to indicate on the navigating
cape routes within accommodation spaces. bridge any loss or reduction of the required ventilating
capacity.
13.3 Cabin balconies (see B.13.3).
Arrangements shall be provided to permit a rapid shut-
down and effective closure of the ventilation system in
14. Protection of vehicle, special category and
case of fire, taking into account the weather and sea
ro-ro spaces
conditions.
14.1 The subdivision of such spaces in main verti- Ventilation ducts, including dampers, within a com-
cal zones would defeat their intended purpose. There- mon horizontal zone shall be made of steel.
fore equivalent protection shall be obtained in such
Ducts passing through other horizontal zones or ma-
spaces on the basis of a horizontal zone concept. A
chinery spaces shall be "A-60" class steel ducts com-
horizontal zone may include special category and ro-
plying with 9.11.
ro spaces on more than one deck provided that the
total overall clear height for vehicles does not exceed Permanent openings in the side plating, the ends or deck-
10 m, whereas the total overall clear height is the sum head of the spaces shall be so situated that a fire in the
of distances between deck and web frames of the cargo space does not endanger stowage areas and em-
decks forming the horizontal zone. barkation stations for survival craft and accommodati-
on spaces, service spaces and control stations in super-
14.2 Structural Protection structures and deckhouses above the cargo spaces.
The boundary bulkheads and decks of special category
14.5 Fire detection
spaces shall be insulated as required for category (11)
spaces in Tables 22.3 and 22.4, whereas the boundary There shall be provided a fixed fire detection and fire
bulkheads and decks of closed and open ro-ro spaces alarm system of an approved type (see also the GL
shall have fire integrity as required for category (8) Rules for Machinery Installations (I-1-2), Section 12).
spaces in Tables 22.3 and 22.4.
A sample extraction smoke detection system of an
Indicators shall be provided on the navigating bridge approved type (see also the GL Rules for Machinery
which shall indicate when any fire door leading to or Installations (I-1-2), Section 12) may be accepted as
from the special category space is closed. equivalent, except for open ro-ro spaces, open vehicle
spaces and special category spaces.
14.3 Fixed fire-extinguishing system
An efficient fire patrol system shall be maintained in
14.3.1 Vehicle spaces and ro-ro spaces which are special category spaces. In case of a continuous fire
not special category spaces and are capable of being watch at all times during the voyage, a fixed fire de-
sealed from a location outside of the cargo spaces tection and alarm system is not required therein.
shall be fitted with a fixed gas fire-extinguishing sys-
tem of an approved type (see also the GL Rules for 15. Special arrangements in machinery spaces
Machinery Installations (I-1-2), Section 12). of category A

14.3.2 Ro-ro and vehicle spaces not capable of being 15.1 The number of skylights, doors, ventilators,
sealed and special category spaces shall be fitted with openings in funnels to permit exhaust ventilation and
a fixed pressure water spraying system for manual other openings to machinery spaces shall be reduced
operation of an approved type (see also the GL Rules to a minimum consistent with the needs of ventilation
for Machinery Installations (I-1-2), Section 12). and the proper and safe working of the ship.
Chapter 1 Section 22 D Structural Fire Protection I - Part 1
Page 22–28 GL 2012

15.2 Skylights shall be of steel and shall not con- heads. Other boundaries between such spaces shall be
tain glass panels. Suitable arrangements shall be made insulated to "A-60" standard.
to permit the release of smoke in the event of fire,
from the space to be protected. The normal ventilation 16.3 Miscellaneous items
systems may be acceptable for this purpose. The kind and extent of the fire extinguishing equip-
ment are defined in the GL Rules for Machinery In-
15.3 Means of control shall be provided for permit- stallations (I-1-2), Section 12.
ting the release of smoke and such controls shall be lo-
cated outside the space concerned so that, in the event Electrical apparatus and cablings are to meet the re-
of fire, they will not be cut off from the space they quirements of the GL Rules for Electrical Installations
serve. The controls shall be situated at one control po- (I-1-3), Section 14.
sition or grouped in as few positions as possible. Such
positions shall have safe access from the open deck. 17. Safety centre on passenger ships

15.4 Such doors other than power-operated water- 17.1 Application

tight doors shall be arranged so that positive closure is
assured in case of fire in the space, by power-operated Passenger ships constructed on or after 1 July 2010
closing arrangements or by the provision of self- shall have on board a safety centre complying with the
closing doors capable of closing against an inclination requirements of this regulation.
of 3,5° opposing closure and having a fail-safe hook-
17.2 Location and arrangement
back facility, provided with a remotely operated re-
lease device. Doors for emergency escape trunks need The safety centre shall either be a part of the naviga-
not be fitted with a fail-safe hold-back facility and a tion bridge or be located in a separate space adjacent
remotely operated release device. to and having direct access to the navigation bridge, so
that the management of emergencies can be performed
15.5 Means of control shall be provided for clos- without distracting watch officers from their naviga-
ing power-operated doors or actuating release mecha- tional duties.
nism on doors other than power-operated watertight
doors. The control shall be located outside the space 17.3 Layout and ergonomic design
concerned, where they will not be cut off in the event
of fire in the space it serves. The means of control The layout and ergonomic design of the safety centre
shall be situated at one control position or grouped in shall take into account the IMO guidelines 16 (com-
as few positions as possible having direct access and munication and control and monitoring of safety sys-
safe access from the open deck. tems see also the GL Rules for Electrical Installations
(I-1-3), Section 14).
15.6 Windows shall not be fitted in machinery
space boundaries. This does not preclude the use of
glass in control rooms within the machinery spaces. D. Passenger Ships with 3 or more Main Ver-
15.7 The floor plating of normal passageways tical Zones or with a Load Line Length of
shall be made of steel. 120 m and over

1. The requirements of this Sub-section are

16. Special requirements for ships carrying additional to those of B. or C.
dangerous goods
2. Ships constructed on or after 1 July 2010 having
16.1 Ventilation a load line length of 120 m and over or with three or more
Adequate power ventilation shall be provided in en- main vertical zones are required to meet design specifica-
closed cargo spaces. The arrangement shall be such as tions in accordance with Chapter II-2 of SOLAS 74 for
to provide for at least six air changes per hour in the – a ship's safe return to port under its own propul-
cargo space based on an empty cargo space and for sion after a fire or flooding casualty
removal of vapours from the upper or lower parts of
the cargo space, as appropriate. – systems required to remain operational for support-
ing the orderly evacuation and abandonment of a
The fans shall be such as to avoid the possibility of ship when exceeding the casualty threshold and
ignition of flammable gas air mixtures. Suitable wire
mesh guard shall be fitted over inlet and outlet ventila- – safe areas.
tion openings. Any impacts thereof on issues addressed elsewhere in this
Section are to be reported in an engineering analysis.
16.2 Insulation of machinery space boundaries
Bulkheads forming boundaries between cargo spaces 3. A safe area is any area which is not flooded
and machinery spaces of category A shall be insulated or which is outside the main vertical zones in which a
to "A-60" standard, unless the dangerous goods are fire has occurred such that it can safely accommodate
stowed at least 3 m horizontally away from such bulk- all persons on board to protect them from hazards to
I - Part 1 Section 22 E Structural Fire Protection Chapter 1
GL 2012 Page 22–29

life or health. Safe areas shall provide all occupants by 10.2 for the detection and extinction of fire in all
with shelter from weather and access to life-saving ap- spaces in which fire might be expected to originate,
pliances, taking into account that a main vertical zone generally with no restriction on the type of internal
may not be available for internal transit. They shall gener- divisional bulkheading; or
ally be internal spaces, unless particular circumstances
allow for an external location, considering any restriction 2.1.3 Method IIIC The fitting of a fixed fire detec-
due to the area of operation and relevant expected envi- tion and fire alarm system, as required by 10.3, in all
ronmental conditions. spaces in which a fire might be expected to originate,
generally with no restriction on the type of internal divi-
sional bulkheading, except that in no case shall the area
of any accommodation space or spaces bounded by an
E. Cargo Ships of 500 GT and over "A" or "B" class division exceed 50 m2. Consideration
may be given to increasing this area for public spaces.
1. Materials
2.2 The requirements for the use of non-combustible
1.1 The hull, decks, structural bulkheads, super- materials in construction and insulation of the boundary
structures and deckhouses are to be of steel except bulkheads of machinery spaces, control stations, service
where in special cases the use of other suitable mate- spaces, etc., and the protection of stairway enclosures
rial may be approved, having in mind the risk of fire. and corridors will be common to all three methods.

1.2 Components made from aluminium alloys 3. Bulkheads within the accommodation and
require special treatment, with regard to the mechani- service spaces
cal properties of the material in case of temperature
increase. In principle, the following is to be observed: 3.1 All bulkheads required to be "B" class divi-
sions shall extend from deck to deck and to the shell
1.2.1 The insulation of "A" or "B" class divisions or other boundaries, unless continuous "B" class ceil-
shall be such that the temperature of the structural core ings or linings are fitted on both sides of the bulkhead
does not rise more than 200 °C above the ambient in which case the bulkhead may terminate at the con-
temperature at any time during the applicable fire tinuous ceiling or lining.
exposure to the standard fire test.
3.2 Method IC
1.2.2 Special attention shall be given to the insula-
tion of aluminium alloy components of columns, stan- All bulkheads not required by this or other require-
chions and other structural members required to support ments of this Section to be "A" or "B" class divisions,
lifeboat and liferaft stowage, launching and embarka- shall be of at least "C" class construction.
tion areas, and "A" and "B" class divisions to ensure:
3.3 Method IIC
that for such members supporting lifeboat and liferaft
areas and "A" class divisions, the temperature rise There shall be no restriction on the construction of
limitation specified in 1.2.1 shall apply at the end of bulkheads not required by this or other requirements
one hour; and of this Section to be "A" or "B" class divisions except
in individual cases where "C" class bulkheads are
that for such members required to support "B" class required in accordance with Table 22.5.
divisions, the temperature rise limitation specified in
1.2.1 shall apply at the end of half an hour. 3.4 Method IIIC
1.2.3 Crowns and casings of machinery spaces of There shall be no restriction on the construction of
category A shall be of steel construction and be insu- bulkheads not required by this Section to be "A" or "B"
lated as required by Table 22.5 as appropriate. Open- class divisions except that the area of any accommoda-
ings therein, if any, shall be suitably arranged and tion space or spaces bounded by a continuous "A" or
protected to prevent the spread of fire. "B" class division shall in no case exceed 50 m2 except
in individual cases where "C" class bulkheads are re-
2. Accommodation and service spaces quired in accordance with Table 22.5. Consideration
may be given to increasing this area for public spaces.
2.1 One of the following methods of protection
shall be adopted in accommodation and service areas: 4. Fire integrity of bulkheads and decks

2.1.1 Method IC The construction of all internal 4.1 In addition to complying with the specific
divisional bulkheading of non-combustible "B" or "C" provisions for fire integrity of bulkheads and decks
class divisions generally without the installation of an mentioned elsewhere in this Section, the minimum fire
automatic sprinkler, fire detection and fire alarm sys- integrity of bulkheads and decks shall be as prescribed
tem in the accommodation and service spaces, except in Tables 22.5 and 22.6.
as required by 10.1; or
4.2 On ships intended for the carriage of danger-
2.1.2 Method IIC The fitting of an automatic sprin- ous goods the bulkheads forming boundaries between
kler, fire detection and fire alarm system, as required cargo spaces and machinery spaces of category A shall
Chapter 1 Section 22 E Structural Fire Protection I - Part 1
Page 22–30 GL 2012

be insulated to "A-60" standard, unless the dangerous Tables 22.5 and 22.6 shall apply respectively to the
goods are stowed at least 3 m horizontally away from bulkheads and decks separating adjacent spaces.
such bulkheads. Other boundaries between such
spaces shall be insulated to "A-60" standard. 4.6 For determining the appropriate fire integrity
standards to be applied to divisions between adjacent
4.3 Continuous "B" class ceilings or linings, in spaces, such spaces are classified according to their
association with the relevant decks or bulkheads, may fire risk as shown in the following categories 1 to 11.
be accepted as contributing, wholly or in part, to the Where the contents and use of a space are such that
required insulation and integrity of a division. there is a doubt as to its classification for the purpose
of this regulation, or where it is possible to assign two
4.4 External boundaries which are required in 1.1 or more classifications to a space, it shall be treated as
to be of steel or other equivalent material may be pierced a space within the relevant category having the most
for the fitting of windows and sidescuttles provided stringent boundary requirements. Smaller, enclosed
that there is no requirement for such boundaries to room within a space that have less than 30 % commu-
have "A" class integrity elsewhere in these require- nicating openings to that space are to be considered
ments. Similarly, in such boundaries which are not separate spaces. The fire integrity of the boundary
required to have "A" class integrity, doors may be of bulkheads of such smaller rooms shall be as prescribed
materials to meet the requirements of their application. in Tables 22.5 and 22.6. The title of each category is
intended to be typical rather than restrictive. The num-
4.5 The following requirements shall govern ber in parentheses preceding each category refers to the
application of the Tables: applicable column or row number in the tables.

Table 22.5 Fire integrity of bulkheads separating adjacent spaces

Spaces [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11]
Control stations [1] A–05 A–0 A–60 A–0 A–15 A–60 A–15 A–60 A–60 10 A–60
Corridors [2] C B–0 B–0 B–0 A–60 A–0 A–0 A–0 10 A–30
A–0 3
Accommodation spaces [3] C1, 2 B–0 B–0 A–60 A–0 A–0 A–0 10 A–30
A–0 3
Stairways [4] B–0 B–0 A–60 A–0 A–0 A–0 10 A–30
A–0 3 A–03 10
Service spaces (low risk)) [5] C A–60 A–0 A–0 A–0 10 A–0
Machinery spaces of category A [6] 10 A–0 A–0 7 A–60 10 A–606
Other machinery spaces [7] A–04 A–0 A–0 10 A–0
Cargo spaces [8] 10 A–0 10 A–0
Service spaces (high risk) [9] A–04 10 A–30
Open decks [10] – A–0
Ro/ro cargo spaces [11] 10,8
Notes to be applied to Tables 22. 5 and 22.6, as appropriate
1 No special requirements are imposed upon bulkheads in methods IIC and IIIC fire protection.
2 In case of method IIC "B" class bulkheads of "B–0" rating shall be provided between spaces or groups of spaces of 50 m 2 a nd over in area.
3 For clarification as to which applies, see 3. and 5.
4
Where spaces are of the same numerical category and superscript 4 appears, a bulkhead or deck of the rating shown in the Tables in only
required when the adjacent spaces are for a different purpose, e.g. in category 9. A galley next to a galley does not require a bulkhead but
a galley next to a paint room requires an "A–0" bulkhead.
5 Bulkheads separating the wheelhouse, chartroom and radio room from each other may be "B–0" rating.
6 A–0 rating may be used if no dangerous goods are intended to be carried or if such goods are stowed not less than 3 m horizontally from
such bulkhead.
7 For cargo spaces in which dangerous goods are intended to be carried, 4.2 applies.
8 Bulkheads and deck sepa rating ro/ro cargo spaces sha ll be capable of being closed reasonably gastight a nd such divisions shall have "A"
class integrity in so far as is reasonable and practicable.
9 Fire insulation need not be fitted if the machinery space in category 7, has little or no fire risk.
10 Where a 10 appears in the Tables, the division is required to be of steel or other equivalent material but is not required to be of "A" class standard.
I - Part 1 Section 22 E Structural Fire Protection Chapter 1
GL 2012 Page 22–31

Table 22.6 Fire integrity of decks separating adjacent spaces

Space above
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11]
Space below
Control stations [1] A–0 A–0 A–0 A–0 A–0 A–60 A–0 A–0 A–0 10 A–60
Corridors [2] A–0 10 10 A–0 10 A–60 A–0 A–0 A–0 10 A–30
Accommodations spaces [3] A–60 A–0 10 A–0 10 A–60 A–0 A–0 A–0 10 A–30
Stairways [4] A–0 A–0 A–0 10 A–0 A–60 A–0 A–0 A–0 10 A–30
Service spaces (low risk) [5] A–15 A–0 A–0 A–0 10 A–60 A–0 A–0 A–0 10 A–0
Machinery spaces of category A [6] A–60 A–60 A–60 A–60 A–60 10 A–609 A–30 A–60 10 A–60
Other machinery spaces [7] A–15 A–0 A–0 A–0 A–0 A–0 10 A–0 A–0 10 A–0
Cargo spaces [8] A–60 A–0 A–0 A–0 A–0 A–0 A–0 10 A–0 10 A–0
Service spaces (high risk) [9] A–60 A–0 A–0 A–0 A–0 A–60 A–0 A–0 A–04 10 A–30

Open decks [10] 10 10 10 10 10 10 10 10 10 – 10

Ro/ro cargo spaces [11] A–60 A–30 A–30 A–30 A–0 A–60 A–0 A–0 A–30 10 10,8
See notes under Table 22.5.

[1] Control stations [6] Machinery spaces of category A

Spaces containing emergency sources of power Spaces and trunks to such spaces which contain:
and lighting. Wheelhouse and chartroom. internal combustion machinery used for main
Spaces containing the ship's radio equipment.
propulsion; or
Fire control stations. Control room for propul-
sion machinery when located outside the ma- internal combustion machinery used for pur-
chinery space. Spaces containing centralized fire poses other than main propulsion where such
alarm equipment. machinery has in the aggregate a total power
output of not less than 375 kW; or
[2] Corridors any oil-fired boiler or oil fuel unit.
Corridors and lobbies.
[7] Other machinery spaces
[3] Accommodation spaces Spaces, other than machinery spaces of category
Spaces used for public spaces, lavatories, cab- A, containing propulsion machinery, boilers, oil
ins, offices, hospitals, cinemas, games and fuel units, steam and internal combustion en-
hobby rooms, barber ships, pantries containing gines, generators and major electrical machin-
no cooking appliances and similar spaces. ery, oil filling stations, refrigerating, stabilizing,
ventilation and air conditioning machinery, and
similar spaces, and trunks to such spaces. Elec-
[4] Stairways
trical equipment rooms (auto-telephone ex-
Interior stairways, lifts, totally enclosed emer- change, air-conditioning duct spaces)
gency escape trunks and escalators (other than
those wholly contained within the machinery [8] Cargo spaces
spaces) and enclosures thereto. All spaces used for cargo (including cargo oil
In this connection, a stairway which is enclosed tanks) and trunkways and hatchways to such
only at one level shall be regarded as part of the spaces.
space from which it is not separated by a fire
door. [9] Service spaces (high risk)
Galleys, pantries containing cooking appliances,
[5] Service spaces (low risk)
saunas, paint and lamp rooms, lockers and store-
Lockers and store-rooms not having provisions rooms having areas of 4 m2 or more, spaces for
for the storage of flammable liquids and having the storage of flammable liquids, and workshops
areas less than 4 m² and drying rooms and laun- other than those forming part of the machinery
dries. spaces.
Chapter 1 Section 22 E Structural Fire Protection I - Part 1
Page 22–32 GL 2012

[10] Open decks A shall be reasonably gastight and self-closing. In

ships constructed according to method IC the use of
Open deck spaces and enclosed promenades combustible materials in doors separating cabins from
having no fire risk. Enclosed promenades shall individual interior sanitary accommodation such as
have no significant fire risk, meaning that fur- showers may be permitted.
nishing should be restricted to deck furniture. In
addition, such spaces shall be naturally venti- 6.4 Doors required to be self-closing shall not be
lated by permanent openings. Air spaces (the fitted with hold-back hooks. However, hold-back
space outside superstructures and deckhouses). arrangements fitted with remote release devices of the
[11] Ro-ro and vehicle spaces fail-safe type may be utilized.

6.5 In corridor bulkheads ventilation openings

5. Protection of stairways and lift trunks in may be permitted only in and under class B-doors of
accommodation spaces, service spaces and cabins and public spaces. Ventilation openings are
control stations also permitted in B-doors leading to lavatories, of-
fices, pantries, lockers and store rooms. Except as
5.1 Stairways which penetrate only a single deck
permitted below, the openings shall be provided only
shall be protected at least at one level by at least "B-0"
in the lower half of a door. Where such opening is in
class divisions and self-closing doors. Lifts which pene-
or under a door the total net area of any such opening
trate only a single deck shall be surrounded by "A-0"
or openings shall not exceed 0,05 m2. Alternatively, a
class divisions with steel doors at both levels. Stairways
non-combustible air balance duct routed between the
and lift trunks which penetrate more than a single deck
cabin and the corridor, and located below the sanitary
shall be surrounded by at least "A-0" class divisions
unit is permitted where the cross-sectional area of the
and be protected by self-closing doors at all levels.
duct does not exceed 0,05 m2. Ventilation openings,
5.2 On ships having accommodation for 12 per- except those under the door, shall be fitted with a
sons or less, where stairways penetrate more than a grille made of non-combustible material.
single deck and where there are at least two escape
routes direct to the open deck at every accommodation 6.6 Watertight doors need not be insulated.
level, consideration may be given reducing the "A-0"
requirements of 5.1 to "B-0". 7. Ventilation systems

5.3 All stairways shall be of steel frame construc- 7.1 Ventilation ducts shall be of steel or equiva-
tion or of other equivalent material. lent material. Short ducts, however, not generally
exceeding 2 m in length and with a cross-section not
6. Openings in fire resisting divisions exceeding 0,02 m2 need not be steel or equivalent,
subject to the following conditions:
6.1 Where "A" or "B" class divisions are pene-
trated for the passage of electric cables, pipes, trunks, 7.1.1 subject to 7.1.2 these ducts shall be of any
ducts, etc. or for girders, beams or other structural material having low flame spread characteristics
members, arrangements shall be made to ensure that which is type approved 4.
the fire resistance is not impaired. 7.1.2 on ships constructed on or after 1 July 2010,
6.2 Except for hatches between cargo, special the ducts shall be made of heat resisting non-com-
category, store, and baggage spaces, and between such bustible material, which may be faced internally and
spaces and the weather decks, all openings shall be externally with membranes having low flame-spread
provided with permanently attached means of closing characteristics and, in each case, a calorific value 5 not
which shall be at least as effective for resisting fires as exceeding 45 MJ/m2 of their surface area for the
the divisions in which they are fitted 3. thickness used;
7.1.3 they may only be used at the end of the venti-
6.3 The fire resistance of doors shall be equiva-
lation device;
lent to that of the division in which they are fitted.
Doors approved as "A" class without the sill being part 7.1.4 they shall not be situated less than 600 mm,
of the frame, which are installed on or after 1 July 2010, measured along the duct, from an opening in an "A" or
shall be installed such that the gap under the door does "B" class division including continuous "B" class
not exceed 12 mm and a non-combustible sill shall be ceilings.
installed under the door such that floor coverings do
not extend beneath the closed door. Doors approved as 7.2 Where a thin plated duct with a free cross-
"B" class without the sill being part of the frame, sectional area equal to, or less than, 0,02 m2 passes
which are installed on or after 1 July 2010, shall be through "A" class bulkheads or decks, the opening
installed such that the gap under the door does not ex- shall be lined with a steel sheet sleeve having a thick-
ceed 25 mm. Doors and door frames in "A" class divi- ness of at least 3 mm and a length of at least 200 mm,
sions shall be constructed of steel. Doors in "B" class divided preferably into 100 mm on each side of the
divisions shall be non-combustible. Doors fitted in bulkhead or, in the case of the deck, wholly laid on the
boundary bulkheads of machinery spaces of category lower side of the decks pierced.
I - Part 1 Section 22 E Structural Fire Protection Chapter 1
GL 2012 Page 22–33

Where ventilation ducts with a free cross-sectional event of fire the machinery and equipment contained
area exceeding 0,02, m2 pass through "A" class bulk- therein may be supervised and continue to function
heads or decks, the opening shall be lined with a steel effectively. Alternative and separate means of air
sheet sleeve. However, where such ducts are of steel supply shall be provided; air inlets of the two sources
construction and pass through a deck or bulkhead, the of supply shall be so disposed that the risk of both
ducts and sleeves shall comply with the following: inlets drawing in smoke simultaneously is minimized.
Such requirements need not apply to control stations
7.2.1 The sleeves shall have a thickness of at least situated on, and opening on to, an open deck.
3 mm and a length of at least 900 mm. When passing
through bulkheads, this length shall be divided pref- 7.6 The ventilation system for machinery spaces
erably into 450 mm on each side of the bulkhead. of category A, vehicle spaces, ro-ro spaces, galleys,
These ducts, or sleeves lining such ducts, shall be special category spaces and cargo spaces shall, in
provided with fire insulation. The insulation shall have general, be separated from each other and from the
at least the same fire integrity as the bulkhead or deck ventilation systems serving other spaces. Except that
through which the duct passes. galley ventilation on cargo ships of less than 4 000
gross tonnage need not be completely separated, but
7.2.2 Ducts with a free cross-sectional area exceed- may be served by separate ducts from a ventilation
ing 0,075 m2 shall be fitted with fire dampers in addi- unit serving other spaces. In any case, an automatic
tion to the requirements of 7.2.1. The fire damper shall fire damper shall be fitted in the galley ventilation
also be capable of being closed manually from both ducts near the ventilation unit.
sides of the bulkhead or deck. The damper shall be
provided with an indicator which shows whether the 7.7 Ducts provided for the ventilation of machin-
damper is open or closed. Fire dampers are not re- ery spaces of category A, galleys, vehicle spaces, ro-ro
quired, however, where ducts pass through spaces cargo spaces or special category spaces shall not pass
surrounded by "A" class divisions, without serving through accommodation spaces, service spaces or
those spaces, provided those ducts have the same fire control stations unless the ducts are either:
integrity as the divisions which they pierce.
7.7.1 constructed of steel having a thickness of at
7.2.3 The following arrangement shall be of an least 3 mm and 5 mm for ducts the widths or diame-
approved type 3. ters of which are up to and including 300 mm and
760 mm and over respectively and, in the case of such
7.2.3.1 fire dampers, including relevant means of ducts, the widths or diameters of which are between
operation 300 mm and 760 mm having a thickness to be ob-
tained by interpolation;
7.2.3.2 duct penetrations through "A" class divisions.
Where steel sleeves are directly joined to ventilation suitably supported and stiffened;
ducts by means of riveted or screwed flanges or by fitted with automatic fire dampers close to the bounda-
welding, the test is not required. ries penetrated; and
7.3 The main inlets and outlets of all ventilation insulated to "A-60" standard from the machinery
systems shall be capable of being closed from outside spaces, galleys, vehicle spaces, ro-ro cargo spaces or
the respective spaces in the event of a fire. special category spaces to a point at least 5 m beyond
each fire damper;
7.4 Where they pass through accommodation or
spaces or spaces containing combustible materials, the 7.7.2 constructed of steel suitable supported and
exhaust ducts from galley ranges shall be constructed stiffened and insulated to "A-60" standard throughout
of insulated "A" class divisions. Each exhaust duct the accommodation spaces, service spaces or control
shall be fitted with: stations.
7.4.1 a grease trap readily removable for cleaning; 7.8 Ducts provided for the ventilation to accom-
7.4.2 a fire damper located in the lower end of the modation spaces, service spaces or control stations
duct and in addition, a fire damper in the upper end of shall not pass through machinery spaces of category
the duct; A, galleys, vehicle spaces, ro-ro cargo spaces or spe-
cial category spaces unless either:
7.4.3 arrangements, operable from within the gal-
ley, for shutting off the exhaust fan; and 7.8.1 the ducts where they pass through a machin-
ery space of category A, galley, vehicle space, ro-ro
7.4.4 fixed means for extinguishing a fire within cargo space or special category space are constructed
the duct (see the GL Rules for Machinery Installations of steel, suitable supported and stiffened and
(I-1-2), Section 12).
automatic fire dampers are fitted close to the bounda-
7.5 Such measures as are practicable shall be ries penetrated; and
taken in respect of control stations outside machinery the integrity of the machinery space, galley, vehicle
spaces in order to ensure that ventilation, visibility and space, ro-ro cargo space or special category space
freedom from smoke are maintained, so that in the boundaries is maintained at the penetrations; or
Chapter 1 Section 22 E Structural Fire Protection I - Part 1
Page 22–34 GL 2012

7.8.2 the ducts where they pass through a machin- 9.3 Methods IC, IIC and IIIC
ery space of category A, galley, vehicle space, ro-ro
cargo space or special category space are constructed 9.3.1 Except in cargo spaces or refrigerated com-
of steel, suitable supported and stiffened, and partments of service spaces, insulating materials shall
be non-combustible. Vapour barriers and adhesives
are insulated to "A-60" standard throughout the accom- used in conjunction with insulation, as well as the
modation spaces, service spaces or control stations. insulation of pipe fittings, for cold service systems,
need not be of non-combustible materials, but they
7.9 Ventilation ducts with a free cross-sectional shall be kept to the minimum quantity practicable and
area exceeding 0,02 m2 passing through "B" class their exposed surfaces shall have low flame spread
bulkheads shall be lined with steel sheet sleeves of characteristics.
900 mm in length divided preferably into 450 mm on
each side of the bulkheads unless the duct is of steel 9.3.2 Where non-combustible bulkheads, linings
for this length. and ceilings are fitted in accommodation and service
spaces they may have a combustible veneer with a
7.10 Power ventilation of accommodation spaces, calorific value 7 not exceeding 45 MJ/m2 of the area
service spaces, cargo spaces, control stations and ma- for the thickness used.
chinery spaces shall be capable of being stopped from an
easily accessible position outside the space being served. 9.3.3 The total volume of combustible facings,
This position should not be readily cut off in the event mouldings, decorations and veneers in any accommo-
of a fire in the spaces served. The means provided for dation and service space bounded by non-combustible
stopping the power ventilation of the machinery bulkheads, ceilings and linings shall not exceed a
spaces shall be entirely separate from the means pro- volume equivalent to a 2,5 mm veneer on the com-
vided for stopping ventilation of other spaces. bined area of the walls and ceilings.

8. Restricted use of combustible materials 9.3.4 Air spaces enclosed behind ceilings, panel-
lings, or linings, shall be divided by close-fitting
8.1 All exposed surfaces in corridors and stair- draught stops spaced not more than 14 m apart. In the
way enclosures and surfaces including grounds in vertical direction, such air spaces, including those
concealed or inaccessible spaces in accommodation behind linings of stairways, trunks, etc., shall be
and service spaces and control stations shall have low closed at each deck.
flame-spread characteristics. Exposed surfaces of
ceilings in accommodation and service spaces (except
10. Fixed fire detection and fire alarm sys-
saunas) and control stations shall have low flame-
tems, automatic sprinkler, fire detection
spread characteristics 4. and fire alarm system
8.2 Paints, varnishes and other finishes used on
exposed interior surfaces shall not offer an undue fire 10.1 In ships in which method IC is adopted, a
hazard and shall not be capable of producing exces- smoke detection system shall be so installed and ar-
ranged as to protect all corridors, stairways and escape
sive quantities of smoke 11.
routes within accommodation spaces.
8.3 Primary deck coverings, if applied, in ac-
commodation and service spaces and control stations 10.2 In ships in which method IIC is adopted, an
shall be of an approved material which will not readily automatic sprinkler, fire detection and fire alarm sys-
ignite, or give rise to toxic or explosive hazardous at tem shall be so installed and arranged as to protect
elevated temperatures 12. accommodation spaces, galleys and other service
spaces, except spaces which afford no substantial fire
risk such as void spaces, sanitary spaces, etc. In addi-
8.4 Waste receptacles (see B.10.10)
tion, a fixed fire detection and fire alarm system shall
be so arranged and installed as to provide smoke de-
9. Details of construction tection in all corridors, stairways and escape routes
within accommodation spaces.
9.1 Method IC
In accommodation and service spaces and control sta- 10.3 In ships in which method IIIC is adopted, a
tions all linings, draught stops, ceilings and their asso- fixed fire detection and fire alarm system shall be so
ciated grounds shall be of non-combustible materials. installed and arranged as to detect the presence of fire
in all accommodation spaces and service spaces, ex-
9.2 Methods IIC and IIIC cept spaces which afford no substantial fire risk such
as void spaces, sanitary spaces, etc. In addition, a
In corridors and stairway enclosures serving accom- fixed fire detection and fire alarm system shall be so
modation and service spaces and control stations, arranged and installed as to provide smoke detection
ceilings, linings, draught stops and their associated in all corridors, stairways and escape routes within
grounds shall be of non-combustible materials. accommodation spaces.
I - Part 1 Section 22 E Structural Fire Protection Chapter 1
GL 2012 Page 22–35

11. Means of escape 11.8 At least two means shall be provided in ro-ro
cargo spaces where the crew are normally employed.
11.1 Unless expressly provided otherwise in this The escape routes shall provide safe escape to the
regulation, at least two widely separated and ready lifeboat and liferaft embarkation decks and shall be
means of escape shall be provided from all spaces and located at the fore and aft ends of the space.
group of spaces. Lifts shall not be considered as form-
ing one of the required means of escape. 11.9 Two means of escape shall be provided from
each machinery space of category A. In particular, one
11.2 Doors in escape routes shall, in general, open of the following provisions shall be complied with:
in-way of the direction of escape, except that
11.9.1 two sets of steel ladders as widely separated
11.2.1 individual cabin doors may open into the as possible leading to doors in the upper part of the
cabins in order to avoid injury to persons in the corri- space similarly separated and from which access is
dor when the door is opened, and provided to the open deck. One of these ladders shall
11.2.2 doors in vertical emergency escape trunks be located within a protected enclosure having fire
may open out of the trunk in order to permit the trunk integrity, including insulation values, in accordance with
to be used both for escape and access. the Tables 22.5 and 22.6 for category (4) space from
the lower part of the space to a safe position outside the
11.3 Stairways and ladders shall be so arranged as space. Self-closing fire doors having the same fire
to provide, from all accommodation spaces and from integrity shall be fitted in the enclosure. The ladder shall
spaces in which the crew is normally employed, other be fixed in such a way that heat is not transferred into
than machinery spaces, ready means of escape to the the enclosure through non-insulated fixing points. The
open deck and thence to the lifeboats and liferafts. In enclosure shall have minimum internal dimensions of
particular the following general provisions shall be at least 800 mm × 800 mm, and shall have emergency
complied with: lighting provisions;
11.3.1 At all levels of accommodation there shall be or
provided at least two widely separated means of es- 11.9.2 one steel ladder leading to a door in the upper
cape from each restricted space or group of spaces. part of the space from which access is provided to the
11.3.2 Below the lowest open deck the main means open deck and additionally, in the lower part of the
of escape shall be a stairway and the second escape space and in a position well separated from the ladder
may be a trunk or a stairway. referred to, a steel door capable of being operated
from each side and which provides access to a safe
11.3.3 Above the lowest open deck the means of escape route from the lower part of the space to the
escape shall be stairways or doors to an open deck or a open deck.
combination thereof.
11.9.3 For a ship of a gross tonnage less than 1 000,
11.4 Stairways and corridors used as means of dispense may be given with one of the means of es-
escape shall be not less than 700 mm in clear width cape due regard being paid to the dimension and dis-
and shall have a handrail on one side. Stairways and position of the upper part of the space.
corridors with a clear width of 1800 mm and above
shall have handrails on both sides. The angle of incli- 11.9.4 In the steering gear room, a second means of
nation of stairways shall be, in general, 45°, but not escape shall be provided when the emergency steering
greater than 50°, and in machinery spaces and small position is located in that space unless there is direct
spaces not more than 60°. Doorways which give ac- access to the open deck.
cess to a stairway shall be of the same size as the
11.10 From machinery spaces other than those of
stairway 13.
category A; two escape routes shall be provided ex-
11.5 Dispense may be given with one of the means cept that a single escape route may be accepted for
of escape, due regard being paid to the nature and spaces that are entered only occasionally, and for
location of spaces and to the numbers of persons who spaces where the maximum travel distance to the door
normally might be quartered or employed there. is 5 m or less.

11.6 No dead-end corridors having a length of 12. Miscellaneous items

more than 7 m shall be accepted. A dead-end corridor
is a corridor or part of a corridor from which there is 12.1 The cargo holds and machinery spaces shall
only one escape route. be capable of being effectively sealed such as to pre-
vent the inlet of air. Doors fitted in boundary bulk-
11.7 If a radiotelegraph station has no direct ac- heads of machinery spaces of category A shall be
cess to the open deck, two means of access to or reasonably gastight and self-closing.
egress from such station shall be provided, one of
which may be a porthole or window of sufficient size 12.2 Construction and arrangement of saunas (see
or other means to provide an emergency escape. B.11.5).
Chapter 1 Section 22 E Structural Fire Protection I - Part 1
Page 22–36 GL 2012

13. Protection of cargo spaces the cargo space does not endanger stowage areas and
embarkation stations for survival craft and accommo-
Fire-extinguishing arrangements in cargo spaces dation spaces, service spaces and control stations in su-
Fire-extinguishing arrangements according to the GL perstructures and deckhouses above the cargo spaces.
Rules for Machinery Installations (I-1-2), Section 12
are to be provided for cargo spaces. 15. Special requirements for ships carrying
dangerous goods
14. Protection of vehicle and ro-ro spaces
15.1 Ventilation
14.1 Fire detection Adequate power ventilation shall be provided in en-
closed cargo spaces. The arrangement shall be such as
There shall be provided a fixed fire detection and fire
to provide for at least six air changes per hour in the
alarm system of an approved type (see also the GL
cargo space based on an empty cargo space and for
Rules for Machinery Installations (I-1-2), Section 12).
removal of vapours from the upper or lower parts of
A sample extraction smoke detection system of an the cargo space, as appropriate.
approved type (see also the GL Rules for Machinery
The fans shall be such as to avoid the possibility of
Installations (I-1-2), Section 12) may be accepted as
ignition of flammable gas air mixtures. Suitable wire
equivalent, except for open ro-ro and vehicle spaces.
mesh guard shall be fitted over inlet and outlet ventila-
tion openings.
14.2 Fire-extinguishing arrangements
Natural ventilation shall be provided in enclosed cargo
14.2.1 Vehicle spaces and ro-ro spaces which are spaces intended for the carriage of solid dangerous
capable of being sealed from a location outside of the goods in bulk, where there is no provision for me-
cargo spaces shall be fitted with a fixed gas fire-extin- chanical ventilation.
guishing system of an approved type (see also the GL
Rules for Machinery Installations (I-1-2), Section 12). 15.2 Insulation of machinery space boundaries
14.2.2 Ro-ro and vehicle spaces not capable of being Bulkheads forming boundaries between cargo spaces
sealed shall be fitted with a fixed pressure water and machinery spaces of category A shall be insulated
spraying system for manual operation of an approved to "A-60" standard, unless the dangerous goods are
type (see also the GL Rules for Machinery Installa- stowed at least 3 m horizontally away from such bulk-
tions (I-1-2), Section 12). heads. Other boundaries between such spaces shall be
insulated to "A-60" standard.
14.3 Ventilation system
Closed vehicle and ro-ro spaces shall be provided with 15.3 Separation of spaces
an effective power ventilation system sufficient to
give at least 6 air changes per hour. Beyond this, a 15.3.1 In ships having ro-ro spaces, a separation shall
higher air exchange rate may be required during the be provided between a closed ro-ro space and an adja-
period of loading and unloading and/or depending on cent open ro-ro space. The separation shall be such as
the electrical installation. The system for such cargo to minimize the passage of dangerous vapours and li-
spaces shall be entirely separate from other ventilation quids between such spaces. Alternatively, such separa-
systems and shall be operating at all times when vehi- tion need not be provided if the ro-ro space is consid-
cles are in such spaces. ered to be a closed cargo space over its entire length
and shall fully comply with the requirements of 14.
Ventilation ducts serving such cargo spaces capable of
being effectively sealed shall be separated for each 15.3.2 In ships having ro-ro spaces, a separation
such space. The system shall be capable of being con- shall be provided between a closed ro-ro space and the
trolled from a position outside such spaces. adjacent weather deck. The separation shall be such as
The ventilation shall be such as to prevent air stratifi- to minimize the passage of dangerous vapours and
cation and the formation of air pockets. liquids between such spaces. Alternatively, a separa-
tion need not be provided if the closed ro-ro spaces are
Means shall be provided to indicate on the navigating in accordance with those required for the dangerous
bridge any loss of the required ventilating capacity. goods carried on the adjacent weather deck.
Arrangements shall be provided to permit a rapid shut-
down and effective closure of the ventilation system in 15.4 Miscellaneous items
case of fire, taking into account the weather and sea The kind and extent of the fire extinguishing equip-
conditions. ment are to meet the requirements of the GL Rules for
Ventilation ducts, including dampers, shall be made of Machinery Installations (I-1-2), Section 12.
steel.
Electrical apparatus and cablings are to meet the re-
Permanent openings in the side plating, the ends or quirements of the GL Rules for Electrical Installations
deckhead of the space shall be so situated that a fire in (I-1-3), Section 16.
I - Part 1 Section 22 F Structural Fire Protection Chapter 1
GL 2012 Page 22–37

F. Oil Tankers of 500 GT and over Bolted plates for the removal of machinery may be
fitted within the limits of such areas.
(These requirements are additional to those of E. ex-
cept as provided otherwise in 3. and 4.) Navigating bridge doors and wheelhouse windows
may be located within this area, so long as they are so
1. Application designed that a rapid and efficient gas and vapour
tightening of the navigating bridge can be ensured.
1.1 Unless expressly provided otherwise, this
Section shall apply to tankers carrying crude oil and 2.3 Windows and side scuttles facing the cargo
petroleum products having a flashpoint not exceeding area and on the sides of the superstructures and deck-
60 °C (closed cup test), as determined by an approved houses within the limits specified in 2.2 shall be of the
flashpoint apparatus, and a Reid vapour pressure fixed (non-opening) type 3.
which is below atmospheric pressure and other liquid Such windows and sidescuttles, except wheelhouse
products having a similar fire hazard. windows, shall be constructed to "A-60" class stan-
dard and shall be of an approved type, except the "A-
1.2 Where liquid cargoes other than those referred 0" class standard is acceptable for windows and side-
to in 1.1 or liquefied gases which introduce additional scuttles outside the limits specified in 2.1.
fire hazards are intended to be carried the require-
ments for ships carrying liquefied gases in bulk, the 2.4 Skylights to cargo pump rooms shall be of
GL Rules for Liquefied Gas Carriers (I-1-6) and the steel, shall not contain any glass and shall be capable
requirements for ships carrying dangerous chemicals of being closed from outside the pump room.
in bulk, the GL Rules for Chemical Tankers (I-1-7)
are to be taken into account. 2.5 Furthermore the requirements of Section 24,
1.3 Tankers carrying petroleum products having A.4. are to be observed.
a flashpoint exceeding 60 °C (closed cup test) as de-
termined by an approved flashpoint apparatus shall 3. Structure, bulkheads within accommoda-
comply with the provisions of E. tion and service spaces and details of con-
struction
1.4 Chemical tankers and gas carriers shall comply For the application of the requirements of E.2., E.3.
with the requirements of this Section, unless other and and E.9. to tankers, only method IC as defined in
additional safety precautions according the requirements E.2.1.1 shall be used.
for ships carrying liquefied gases in bulk, the GL Rules
for Liquefied Gas Carriers (I-1-6) and the requirements
for ships carrying dangerous chemicals in bulk, the GL 4. Fire integrity of bulkheads and decks
Rules for Chemical Tankers (I-1-7) apply.
4.1 In lieu of E.4. and in addition to complying
2. Construction with the specific provisions for fire integrity of bulk-
heads and decks mentioned elsewhere in this Section
2.1 Exterior boundaries of superstructures and the minimum fire integrity of bulkheads and decks
deckhouses enclosing accommodation and including shall be as prescribed in Tables 22.7 and 22.8.
any overhanging decks which support such accommo-
dation shall be constructed of steel and insulated to 4.2 The following requirements shall govern
"A-60" standard for the whole of the portions which application of the Tables:
face the cargo area and on the outward sides for a Tables 22.7 and 22.8 shall apply respectively to the
distance of 3 m from the end boundary facing the bulkhead and decks separating adjacent spaces.
cargo area. In the case of the sides of those superstruc-
tures and deckhouses, such insulation shall be carried 4.3 For determining the appropriate fire integrity
up to the underside of the bridge deck. standards to be applied to divisions between adjacent
spaces, such spaces are classified according to their
2.2 Entrances, air inlets and openings to accom-
fire risk as shown in categories 1 to 10 below. Where
modation spaces, service spaces and control stations
the contents and use of a space are such that there is a
shall not face the cargo area. They shall be located on doubt as to its classification for the purpose of this
the end bulkhead not facing the cargo area and/or on
regulation, or where it is possible to assign two or
the outboard side of the superstructure or deckhouse at
more classifications to a space, it shall be treated as a
a distance of at least 4 % of the length of the ship but space within the relevant category having the most
not less than 3 m from the end of the superstructure or
stringent boundary requirements. Smaller, enclosed
deckhouse facing the cargo area. This distance, how-
rooms within a space that have less than 30% commu-
ever, need not exceed 5 m.
nicating openings to that space are considered separate
In this area doors to those spaces not having access to spaces. The fire integrity of the boundary bulkheads of
accommodation spaces, service spaces and control such smaller rooms shall be as prescribed in Tables
stations, such as cargo control stations, provision 22.7 and 22.8. The title of each category is intended to
rooms, store-rooms and engine rooms may be permit- be typical rather than restrictive. The number in paren-
ted provided that the boundaries of the spaces are theses preceding each category refers to the applicable
insulated to "A-60" standard. column or row in the Tables.
Chapter 1 Section 22 F Structural Fire Protection I - Part 1
Page 22–38 GL 2012

Table 22.7 Fire integrity of bulkheads separating adjacent spaces

Spaces [1] [2] [3] [4] [5] [6] [7] [8] [9] [10]
Control stations [1] A–03 A–0 A–60 A–0 A–15 A–60 A–15 A–60 A–60 6

Corridors [2] C B–0 B–0 B–0 A–60 A–0 A–60 A–0 6

A–01
Accommodation spaces [3] C B–0 B–0 A–60 A–0 A–60 A–0 6
A–01
Stairways [4] B–0 B–0 A–60 A–0 A–60 A–0 6
A–01 A–01
Service spaces (low risk) [5] C A–60 A–0 A–60 A–0 6

Machinery spaces of category A [6] 6 A–0 A–04 A–60 6

Other machinery spaces [7] A–02 A–0 A–0 6

Cargo pump rooms [8] 6 A–60 6

Service spaces (high risk) [9] A–02 6

Open decks [10] –

Notes to be applied to Tables 22.7 and 22.8, as appropriate

1 For clarification as to which applies, see D.3 and D.5
2 Where spaces are of the same numerical category and superscript 2 appears, a bulkhead or deck of the rating shown in the Tables in only
required when the adjacent spaces are for a different purpose, e.g. in category 9. A galley next to a galley does not require a bulkhead but
a galley next to a paint room requires an "A–0" bulkhead.
3 Bulkheads separating the wheelhouse, chartroom and radio room from each other may be"B-0" rating.
4 Bulkheads and decks between cargo pump rooms and machinery spaces of category. A may be penetrated by cargo pump shaft glands
and similar glanded penetra tions, provided that gastight seals with efficient lubrication or other means of ensuring the permanence of the
gas seal are fitted in way of the bulkhead or deck.
5 Fire insulation need not be fitted if the machinery space in category 7 has little or no fire risk.
6 Where a 6 appears in the Tables, the division is required to be of steel or other equivalent material but is not required to be of "A" class
standard.

Table 22.8 Fire integrity of decks separating adjacent spaces

Space above
[1] [2] [3] [4] [5] [6] [7] [8] [9] [10]
Space below
Control stations [1] A–0 A–0 A–0 A–0 A–0 A–60 A–0 – A–0 6

Corridors [2] A–0 6 6 A–0 6 A–60 A–0 – A–0 6

Accommodation spaces [3] A–60 A–0 6 A–0 6 A–60 A–0 – A–0 6

Stairways [4] A–0 A–0 A–0 6 A–0 A–60 A–0 – A–0 6

Service space (low risk) [5] A–15 A–0 A–0 A–0 6 A–60 A–0 – A–0 6

6
Machinery spaces of category A [6] A–60 A–60 A–60 A–60 A–60 A–605 A–0 A–60 6

Other machinery spaces [7] A–15 A–0 A–0 A–0 A–0 A–0 6 A–0 A–0 6

Cargo pump rooms [8] – – – – – A–04 A–0 6 – 6

Service spaces (high risk) [9] A–60 A–0 A–0 A–0 A–0 A–60 A–0 – A–02 6

Open decks [10] 6 6 6 6 6 6 6 6 6 –

See notes under Table 22.7
I - Part 1 Section 22 G Structural Fire Protection Chapter 1
GL 2012 Page 22–39

[1] Control stations [8] Cargo pump rooms

Spaces containing emergency sources of power Spaces containing cargo pumps and entrances
and lighting. Wheelhouse and chartroom. Spaces and trunks to such spaces.
containing the ship's radio equipment. Fire con-
trol stations. Control room for propulsion ma- [9] Service spaces (high risk)
chinery when located outside the machinery Galleys, pantries containing cooking appliances,
space. Spaces containing centralized fire alarm saunas, paint and lamp rooms, lockers and store-
equipment. rooms having areas of 4 m2 or more,
spaces for the storage of flammable liquids, and
[2] Corridors workshops other than those forming part of the
Corridors and lobbies. machinery spaces.

[10] Open decks

[3] Accommodation spaces
Open deck spaces and enclosed promenades
Spaces used for public spaces, lavatories, cab- having little or no fire risk. Air spaces (the space
ins, offices, hospitals, cinemas, games and hob- outside superstructures and deckhouses).
bies rooms, barber shops, pantries containing no
cooking appliances and similar spaces. 4.4 Continuous "B" class ceilings or linings, in
association with the relevant decks or bulkheads, may
[4] Stairways be accepted as contributing wholly or in part, to the
required insulation and integrity of a division.
Interior stairways, lifts, totally enclosed emer-
gency escape trunks and escalators (other than 4.5 External boundaries which are required in
those wholly contained within the machinery E.1. to be of steel or other equivalent material may be
spaces) and enclosures thereto. pierced for the fitting of windows and sidescuttles
provided that there is not requirement for such
In this connection, a stairway which is enclosed boundaries to have "A" class integrity elsewhere in
only at one level shall be regarded as part of the these requirements. Similarly, in such boundaries
space from which it is not separated by a fire which are not required to have "A" class integrity,
door. doors may be of materials to meet the requirements of
their application.
[5] Service spaces (low risk)
4.6 Permanent approved gastight lighting enclo-
Lockers and store-rooms not having provisions sures for illuminating cargo pump rooms may be per-
for the storage of flammable liquids and having mitted in bulkheads and decks separating cargo pump
areas less than 4 m2 and drying rooms and laun- rooms and other spaces provided they are of adequate
dries. strength and the integrity and gastightness of the bulk-
head or deck is maintained.
[6] Machinery spaces of category A
4.7 Construction and arrangement of saunas
Spaces and trunks to such spaces which contain: See B.11.5.
internal combustion machinery used for main
propulsion; or
G. Helicopter Decks
internal combustion machinery used for pur-
poses other than main propulsion where such
machinery has in the aggregate a total power 1. Helicopter decks shall be of a steel or steel
output of not less than 375 kW; or equivalent fire-resistant construction. If the space
below the helicopter deck forms the deckhead of a
any oil-fired boiler or oil fuel unit. deckhouse or superstructure, it shall be insulated to
"A-60" class standard. If an aluminium or other low
[7] Other machinery spaces melting metal construction will be allowed, the fol-
lowing provisions shall be satisfied:
Spaces, other than machinery spaces of category
A, containing propulsion machinery, boilers, oil 1.1 If the platform is cantilevered over the side of
fuel units, steam and internal combustion en- the ship, after each fire on the ship or on the platform,
gines, generators and major electrical machin- the platform shall undergo a structural analysis to
ery, oil filling stations, refrigerating, stabilizing, determine its suitability for further use.
ventilation and air conditioning machinery, and
similar spaces, and trunks to such spaces. Elec- 1.2 If the platform is located above the ship's
trical equipment rooms (auto-telephone ex- deckhouse or similar structure, the following condi-
change and air-conditioning duct spaces). tions shall be satisfied:
Chapter 1 Section 22 G Structural Fire Protection I - Part 1
Page 22–40 GL 2012

1.2.1 the deckhouse top and bulkheads under the 1.2.4 after each fire on the platform or in close
platform shall have no openings; proximity, the platform shall undergo a structural
analysis to determine its suitability for further use.
1.2.2 all windows under the platform shall be pro-
vided with steel shutters; 1.3 A helideck shall be provided with both a
main and an emergency means of escape and access
1.2.3 the required fire-fighting equipment shall be for fire fighting and rescue personnel. These shall be
in accordance with the requirements of the GL Rules located as far as apart from each other as is practicable
for Machinery Installations (I-1-2), Section 12. and preferably on opposite sides of the helideck.
I - Part 1 Section 23 B Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Chapter 1
GL 2012 Cargo and Heavy Cargo Page 23–1

Section 23

Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Cargo
and Heavy Cargo

A. Strengthenings for Bulk Cargo and Heavy

new A.1.5
Cargo
2.4 In the drawings to be submitted, details are to
1. General be given regarding the loads resulting from the cargo,
upon which the calculations are based.
1.1 For ships, occasionally or regularly carrying
heavy cargo, such as iron, ore, phosphate etc., and not
new B.1.3
intended to get the Notation BULK CARRIER (see
B.) or ORE CARRIER (see C.) affixed to their Char- 3. Longitudinal strength
acter of Classification, strengthenings according to the
following requirements are recommended. The longitudinal strength of the ship is to comply with
the requirements of Section 5 irrespective of the ship's

new A.1.2 length.

new B.2
1.2 In addition, these ships have to fulfil IMO
Resolution MSC. 277(85) as defined in the GL Rules B. Bulk Carriers
for Classification and Surveys (I-0), Section 2.
1. General

new A.1.2
1.1 Bulk carriers built in accordance with the
1.3 Ships complying with these requirements will
following requirements will get the Notation BULK
get the Notation STRENGTHENED FOR HEAVY
CARRIER affixed to their Character of Classifica-
CARGO affixed to their Character of Classification. tion.

new A.1.1

new A.1.3
1.4 It is recommended to provide adequate
Entries will be made into the Certificate as to whether
strengthening or protection of structural elements
specified cargo holds may be empty in case of alter-
within the working range of grabs, see also B.4.3.2
nating loading. Additional indications of the types of
and B.9.1.
cargo for which the ship is strengthened may be en-

new A.1.5 tered into the certificate.

I-0, Section 2, Table 2.3
2. Double bottom
Such a ship is considered in this Section a "Single
2.1 Where longitudinal framing is adopted for the Side Skin Bulk Carrier" when one or more cargo holds
double bottom, the spacing of plate floors shall, in are bound by the side shell only or by two watertight
general, not be greater than the height of the double boundaries, one of which is the side shell, which are
bottom. The scantlings of the inner bottom longitudi- less than 1000 mm apart. The distance between the
nals are to be determined for the load of the cargo watertight boundaries is to be measured perpendicular
according to Section 9, B. to the side shell.
For the longitudinal girder system, see Section 8,
new A.3
B.7.5. When the distance is 1000 mm or above in cargo

new B.1.1 length area, such a ship is considered a "Double Side
Skin Bulk Carrier".
2.2 Where transverse framing is adopted for the
new A.3
double bottom, plate floors according to Section 8, B.6.
are to be fitted at every frame in way of the cargo holds. For accessibility see Section 1, D.1.

new B.1.2 1.2 The requirements of Sections 1 to 22 apply to
bulk carriers unless otherwise mentioned in this Sec-
2.3 For strengthening of inner bottom, deep tank tion. A.1.1 is also to be observed.
tops etc. in way of grabs, see B.4.3.
Chapter 1 Section 23 B Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk I - Part 1
Page 23–2 Cargo and Heavy Cargo GL 2012

new A.1.6 For alternate loading conditions Section 8, B.8.2.2 is

to be observed.
1.3 For hull structural design of bulk carriers
new C.2.1.2
with L ≥ 90 m, contracted for construction on or after
1. April 2006 and in accordance with the definition in For ships of 150 m in length and above, Section 5, G.
1.4, the IACS Common Structural Rules for Bulk is to be considered.
Carriers are applicable.
new C.2.2
In addition to BULK CARRIER these ships will be
assigned the Notation CSR. 3. Definitions

I-0, Section 2, Table 2.3 and Table 2.4 k = material factor according to Section 2, B.2.
tK = corrosion addition according to Section 3, K.
1.4 Bulk carrier according to the IACS Common
Structural Rules means a ship which is constructed pbc = bulk cargo pressure as defined in Section 4, C.1.4.
generally with single deck, double bottom, top-side

new A.3
tanks and hopper side tanks in cargo spaces, with
single or double side skin construction in cargo length
area and is intended primarily to carry dry cargo in 4. Scantlings of bottom structure
bulk. Typical midship sections are given in Fig. 23.14.
4.1 General
1.5 For bulk carriers carrying also oil in bulk also The scantlings of double bottom structures in way of
Section 24, G. applies. the cargo holds are to be determined by means of
direct calculations according to Section 8, B.8.

new A.2.2
For ships according to Section 5, G., D. has to be
1.6 Where reduced freeboards according to observed in addition.
ICLL shall be assigned, the respective requirements
new C.3.1
of the ICLL are to be observed.

new C.1 4.2 Floors under corrugated bulkheads
Plate floors are to be fitted under the face plate strips
1.7 The scantlings of the bottom construction are of corrugated bulkheads. A sufficient connection of
to be determined on the basis of direct calculations the corrugated bulkhead elements to the double bot-
according to Section 8, B.8. 1. tom structure is to be ensured. Under the inner bottom,
For ships according to Section 5, G., D. has to be scallops in the above mentioned plate floors are to be
observed in addition. restricted to those required for crossing welds. The
plate floors as well as the face plate strips are to be

new C.3.1 welded to the inner bottom according to the stresses to
be transferred. In general, full or partial penetration
1.8 For corrosion protection for cargo hold welding is to be used, see also E.4.1.1.
spaces see Section 35, G.

new C.3.2

new A.2.3
4.3 Inner bottom and tank side slopes
1.9 For dewatering requirements of forward
spaces of bulk carriers, see the GL Rules for Machin- 4.3.1 The thickness of the inner bottom plating
ery Installations (I-1-2), Section 11, N. including the tank side slopes is to be determined
according to Section 8, B.4.

new A.2.4
When determining the load on inner bottom pi, a cargo
1.10 For water ingress detection systems of bulk density of not less than 1 t/m2 is to be used.
carriers, see the GL Rules for Electrical Installations
(I-1-3), Section 18. For determining scantlings of tank side slopes the load
pi is not to be taken less than the load which results

new A.2.5 from an angle of heel of 20°.

2. Longitudinal strength
new C.3.3.1

The requirements of A.3. apply. 4.3.2 Where the plating has been designed accord-
ing to the following formula, in connection with 9. the

new C.2.1.1
notation G may be entered into the Certificate behind
the Character of Classification:

1
t G = ( 0,1 L + 5 ) k [mm]
Upon request, GL will carry out calculations for the bottom
structure.
I - Part 1 Section 23 B Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Chapter 1
GL 2012 Cargo and Heavy Cargo Page 23–3

The thickness, however, need not exceed 30 mm. where bf and tf are the flange width and thickness of
the brackets, respectively [mm]. The end of the flange
Note is to be sniped.
The stressing of the inner bottom plating depends In ships with L < 190 m, mild steel frames may be
mainly on the use of grabs, therefore, damage of plat- asymmetric and fitted with separate brackets. The face
ing cannot be excluded, even in case of compliance plate or flange of the bracket is to be sniped at both
with the above recommendation. ends. Brackets are to be arranged with soft toes.

new J.2 The web depth to thickness ratio of frames is not to
exceed the following values:
4.3.3 Sufficient continuity of strength is to be pro-
vided for between the structure of the bottom wing hw
= 60 ⋅ k for symmetrically flanged frames
tanks and the adjacent longitudinal structure. tw

new C.3.3.2 hw
= 50 ⋅ k for asymmetrically flanged frames
tw
5. Side structures
The outstanding flange b1 is not to exceed 10 ⋅ k
5.1 Side longitudinals, longitudinal stiffeners, times the flange thickness, see Fig. 23.1.
main frames

new C.4.2.3
The scantlings of side longitudinals are to be deter-
mined according to Section 9, B. The longitudinal In way of the foremost hold, side frames of asymmet-
stiffeners at the lower tank side slopes are to have the rical section are to be fitted with tripping brackets at
same section modulus as the side longitudinals. Their every two frames according to Section 9, A.5.5.
scantlings are also to be checked for the load accord-
new C.4.2.4
ing to 4.3.1. For the longitudinal stiffeners of the top-
side tanks within the upper flange, Section 9, B.1.5 is Where proof of fatigue strength according to Section
to be observed. 20 is carried out for the main frames, this proof is to
be based on the scantlings which do not include the 20

new C.4.1 per cent increase in section modulus.

new C.4.2.5
5.2 Main frames and end connections
For bulk carrier ship configurations which incorporate
The section modulus of main frames of single side hopper and topside tanks the minimum thickness of
skin bulk carriers is to be increased by at least 20 % frame webs in cargo holds and ballast holds is not to
above the value required by Section 9, A.2.1.1. be less than:

new C.4.2.1
t w, min = C ( 7, 0 + 0, 03 L ) [mm]
The section modulus W of the frame and bracket or
integral bracket, and associated shell plating, at the
C = 1,15 for the frame webs in way of the fore-
locations shown in Fig. 23.1, is not to be less than
most hold
twice the section modulus WF required for the frame
midspan area. = 1,00 for the frame webs in way of other
holds
The dimensions of the lower and upper brackets are
not to be less than those shown in Fig. 23.2. where L need not be taken greater than 200 m.
Structural continuity with the upper and lower end
new C.4.2.6
connections of side frames is to be ensured within The thickness of the brackets at the lower frame ends is
topsides and hopper tanks by connecting brackets as not to be less than the required web thickness tw of the
shown in Fig. 23.3. frames or tw,min + 2,0 mm, whichever is the greater value.

new C.4.2.2 The thickness of the frame upper bracket is not to be
Frames are to be fabricated symmetrical sections with less than the greater of tw and tw,min.
integral upper and lower brackets and are to be ar-
new C.4.2.7
ranged with soft toes.
The side frame flange is to be curved (not knuckled) at 5.3 Minimum thickness of side shell plating
the connection with the end brackets. The radius of
The thickness of side shell plating located between
curvature is not to be less than r [mm], given by:
hopper and upper wing tanks is not to be less than
tp,min [mm], given by:
bf2
r = 0, 4
tf
Chapter 1 Section 23 B Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk I - Part 1
Page 23–4 Cargo and Heavy Cargo GL 2012

t p, min = L [mm] 6.4 Sufficient continuity of strength is to be pro-

vided for between the structure of the topside tanks

new C.4.3 and the adjacent longitudinal structure.

5.4 Weld connections of frames and end brackets
new C.5.3

Double continuous welding is to be adopted for the

7. Transverses in the wing tanks
connections of frames and brackets to side shell, hop-
per and upper wing tank plating and web to face plates. Transverses in the wing tanks are to be determined
For this purpose, the weld throat is to be (see Fig. 23.1): according to Section 12, B.3. for the load resulting
from the head of water or for the cargo load. The
– 0,44 ⋅ t in zone "a" greater load is to be considered.
– 0,40 ⋅ t in zone "b"
The scantlings of the transverses in the lower wing tanks
where t is the plate thickness of the thinner of the two are also to be examined for the loads according to 4.3.1.
connected members.

new C.6
Where the hull form is such to prohibit an effective
fillet weld, edge preparation of the web of frame and
8. Cargo hold bulkheads
bracket may be required, in order to ensure the same
efficiency as the weld connection stated above. The following requirements apply to cargo hold bulk-

new C.4.4 heads on the basis of the loading conditions according
to Section 5, A.4.
6. Topside tanks
For vertically corrugated transverse cargo hold bulk-
6.1 The plate thickness of the topside tanks is to heads on ships according to Section 5, G. the require-
be determined according to Section 12. ments of E. apply in addition, where the strength in
the hold flooded condition has to be ensured.

new C.5.1

new C.7.1
6.2 Where the transverse stiffening system is
applied for the longitudinal walls of the topside tanks 8.1 The scantlings of cargo hold bulkheads are to
and for the shell plating in way of the topside tanks, be determined on the basis of the requirements for tank
the stiffeners of the longitudinal walls are to be de- structures according to Section 12, B., where the load pbc
signed according to Section 12, the transverse frames according to Section 4, C.1.4 is to be used for the load p.
at the shell according to Section 9, A.3.

new C.7.2

new C.5.2

6.3 The buckling strength of top side tank struc- 8.2 The scantlings are not to be less than those re-
tures is to examined in accordance with Section 3, F. quired for watertight bulkheads acc. to Section 11. The
plate thickness is in no case to be taken less than 9,0 mm.

new Section 3, D.1.1

new C.7.3
I - Part 1 Section 23 B Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Chapter 1
GL 2012 Cargo and Heavy Cargo Page 23–5

upper wing tank

zone "a"

Wupper = 2 × WF
bracket

0.25
r

bf hw
b1 b1
zone "b"
tf
WF
tw 0.44 × t in zone "a" t = the lesser of
0.40 × t in zone "b" tp and tw
tp (tw and tf)

0.25
Wlower = 2 × WF
bracket

zone "a"

lower wing tank

Fig. 23.1 Side frame of single side skin bulk carrier

0.5d
(in general)

soft toe
0.125

d
web height

Fig. 23.2 Dimensions of the upper and lower Fig. 23.3 Connecting bracket in the hopper
bracket of the side frames tank
Chapter 1 Section 23 B Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk I - Part 1
Page 23–6 Cargo and Heavy Cargo GL 2012

8.3 The scantlings of the cargo hold bulkheads
new J.4

are to be verified by direct calculations. Permissible
stresses are given in Section 11, B.5.3.1. 10. Loading information for Bulk Carriers,

new C.7.4 Ore Carriers and Combination Carriers

8.4 Above vertically corrugated bulkheads, trans- 10.1 General, definitions

verse girders with double webs are to be fitted below 10.1.1 These requirements are additional to those
the deck, to form the upper edge of the corrugated specified in Section 5, A.4.4 and apply to Bulk Carri-
bulkheads. They are to have the following scantlings: ers, Ore Carriers and Combination Carriers of 150 m
– web thickness = thickness of the upper plate strake length and above and are minimum requirements for
of the bulkhead loading information.

– depth of web ≈ B/22
new C.9.1.1

– face plate = 1,5 times the thickness of the 10.1.2 All ships falling into the category of this
(thickness) upper plate strake of the bulkhead Section are to be provided with an approved loading
See also E.4.1.3. manual and an approved computer-based loading
instrument.

new C.7.5

new C.9.1.2
8.5 Vertically corrugated transverse cargo hold
bulkheads are to have a plane stiffened strip of plating 10.1.3 The following definitions apply:
at the ship's sides. The width of this strip of plating is Loading manual is a document which in addition to
to be 0,15 H where the length of the cargo hold is the definition given in Section 5, A.4.1.3 describes:
20 m. Where the length of the cargo hold is
greater/smaller, the width of the strip of plating is to – for bulk carriers, envelope results and permissi-
be increased/reduced proportionally. ble limits of still water bending moments and
shear forces in the hold flooded condition ac-

new C.7.6 cording to Section 5, G.

9. Hatchway coamings, longitudinal bulkheads – which cargo hold(s) or combination of cargo

holds might be empty at full draught. If no cargo
9.1 Coamings hold is allowed to be empty at full draught, this
is to be clearly stated in the loading manual.
The scantlings of the hatchway coaming plates are to
be determined such as to ensure efficient protection – maximum allowable and minimum mass re-
against mechanical damage by grabs. quired of cargo and double bottom contents of
each hold as a function of the draught at mid-
Wire rope grooving in way of cargo holds openings is hold position.
to be prevented by fitting suitable protection such as
half-round bar on the hatch side girders (i.e. upper – maximum allowable and minimum required
portion of top side tank plates), hatch end beams in mass of cargo and double bottom contents of
cargo hold and upper portion of hatch coamings. any two adjacent holds as a function of the mean
draught in way of these holds. This mean
The coaming plates are to have a minimum thickness draught may be calculated by averaging the
of 15 mm. Stays shall be fitted at every alternate frame. draught of the two mid-hold positions.
The longitudinal hatchway coamings are to be extend-
ed in a suitable manner beyond the hatchway corners. – maximum allowable tank top loading together
with specification of the nature of cargo for car-

new J.3 goes other than bulk cargoes.
In way of the hatchway corners full penetration weld- – maximum allowable load on deck and hatch
ing by means of double bevel T-joints or single bevel covers. If the vessel is not approved to carry
T-joints may be required for connecting the coaming load on deck or hatch covers, this is to be clearly
with the deck plating. stated in the loading manual.
See also Section 17. – the maximum rate of ballast change together

new C.8 with the advice that a load plan is to be agreed
with the terminal on the basis of the achievable
9.2 Longitudinal bulkheads rates of change of ballast.

Where longitudinal bulkheads exposed to grabs have Loading instrument is an approved computer system
got a general corrosion addition according to Section which in addition to the requirements given in Section
5, A.4.1.3 shall be capable to ascertain that:
3, K.2. of tK = 2,5 mm in connection with 4.3.2 and
9.1 the Notation G may be entered into the Certificate
behind the Character of Classification.
I - Part 1 Section 23 C Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Chapter 1
GL 2012 Cargo and Heavy Cargo Page 23–7

– allowable mass of cargo and double bottom 10.3 Condition of approval of loading instru-
contents in way of each cargo hold as a function ments
of the ship's draught at mid-hold position
The loading instrument and its operation manual are
– allowable mass of cargo and double bottom subjected to approval. In addition to the requirements
contents in any two adjacent cargo holds as a given in Section 5, A.4.5.1 the approval is to include:
function of the mean draught in way of these
– acceptance of actual hull girder bending moment
holds and
limits for all read out points
– the still water bending moments and shear
– acceptance of actual hull girder shear force
forces in the hold flooded condition according to
limits for all read out points
Section 5, G.
– acceptance of limits for mass of cargo and dou-
are within permissible values.
ble bottom contents of each hold as a function of

new C.9.1.3 draught
– acceptance of limits for mass of cargo and dou-
10.2 Conditions of approval of loading manuals ble bottom contents in any two adjacent holds as
In addition to the requirements given in Section 5, A. a function of the mean draught in way of these
4.2 the following loading conditions, subdivided into holds
departure and arrival conditions as appropriate, are to
new C.9.3
be included in the loading manual:
– alternate light- and heavy cargo loading condi-
tions at maximum draught, where applicable
– homogeneous light- and heavy cargo loading C. Ore Carriers
conditions at maximum draught
1. General
– ballast conditions including those conditions,
where ballast holds are filled when the adjacent 1.1 Ore carriers are generally single-deck vessels
topwing-, hopper- and double bottom tanks are with the machinery aft and two continuous longitudi-
empty. nal bulkheads with the ore cargo holds fitted between
– short voyage conditions where the vessel is to be them, a double bottom throughout the cargo length
loaded to maximum draught but with limited area and intended primarily to carry ore cargoes in the
amount of bunkers centre holds only.
– multiple port loading/unloading conditions
new A.3
– deck cargo conditions, where applicable 1.2 Ships built in accordance with the following
– typical loading sequences where the vessel is requirements will get the Notation ORE CARRIER
loaded from commencement of cargo loading to affixed to their Character of Classification. Entries
reaching full dead weight capacity, for homoge- will be made into the Certificate as to whether speci-
neous conditions, relevant part load conditions fied cargo holds may be empty in case of alternating
load-ing. Additional indications of the types of cargo
and alternate conditions, where applicable.
for which the ship is strengthened may be entered into
Typical unloading sequences for these condi-
the Certificate.
tions shall also be included. The typical load-
ing/unloading sequences shall also be developed
I-0, Section 2, Table 2.3
to not exceed applicable strength limitations.
The typical loading sequences shall also be de- 1.3 For ships subject to the provisions of this
veloped paying due attention to loading rate and paragraph the requirements of B. are applicable unless
the deballasting capability 2. otherwise mentioned in this sub-section.
– typical sequences for change of ballast at sea,
new A.1.4
where applicable
1.4 For ore carriers carrying also oil in bulk also

new C.9.2 Section 24, G. applies.

new A.2.2

1.5 Where reduced freeboards according to

ICLL shall be assigned, the respective requirements
of the ICLL are to be observed.
2 Reference is made to IACS Recommendation No. 83 (August
2003), "Notes to Annexes to IACS Unified Requirements S1A
new D.1
on Guidance for Loading/Unloading Sequences for Bulk Car-
riers.
Chapter 1 Section 23 D Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk I - Part 1
Page 23–8 Cargo and Heavy Cargo GL 2012

2. Double bottom For each loading condition, the maximum bulk cargo
density to be carried is to be considered in calculating
2.1 For achieving good stability criteria in the the allowable hold loading limit.
loaded condition the double bottom between the longi-
tudinal bulkheads should be as high as possible.
new E.2.1

new D.2.1 2.2 Inner bottom flooding head

2.2 The strength of the double bottom structure is The flooding head hf (see Fig. 23.4) is the distance
to comply with the requirements given in B.4. [m], measured vertically with the ship in the upright
position, from the inner bottom to a level located at a

new D.2.2 distance df [m], from the baseline:

3. Transverse and longitudinal bulkheads df is in general:

– H for the foremost hold
3.1 The spacing of transverse bulkheads in the
side tanks which are to be used as ballast tanks is to be – 0,9 ⋅ H for the other holds
determined according to Section 24, as for tankers. The
spacing of transverse bulkheads in way of the cargo For ships less than 50 000 tonnes deadweight with
hold is to be determined according to Section 11. Type B freeboard, df is:

new D.3.1 – 0,95 ⋅ H for the foremost hold
– 0,85 ⋅ H for the other holds
3.2 The scantlings of cargo hold bulkheads ex-
posed to the load of the ore cargo are to be determined
new E.2.2
according to B.8. The scantlings of the side longitudi-
nal bulkheads are to be at least equal to those required
3. Shear capacity of the double bottom
for tankers.

new D.3.2 The shear capacity C of the double bottom is defined
as the sum of the shear strength at each end of:
– all floors adjacent to both hoppers, less one half
D. Allowable hold loading, considering flood- of the strength of the two floors adjacent to each
ing stool, or transverse bulkhead if no stool is fitted,
see Fig. 23.5
1. General – all double bottom girders adjacent to both stools,
or transverse bulkheads if no stool is fitted
These requirements apply to all bulk carriers, defined
in Section 5, G. Where in the end holds, girders or floors run out and
The loading in each hold is not to exceed the allow- are not directly attached to the boundary stool or hop-
able loading according to 4. and shall not exceed the per girder, their strength is to be evaluated for the one
design hold loading in intact condition. end only.

new E.1 The floors and girders to be considered are those in-
side the hold boundaries formed by the hoppers and
2. Load model stools (or transverse bulkheads if no stool is fitted).
The hopper side girders and the floors directly below
2.1 General the connection of the bulkhead stools (or transverse
The loads to be considered as acting on the double bulkheads if no stool is fitted) to the inner bottom are
bottom are those given by the external sea pressures not to be included.
and the combination of the cargo loads with those When the geometry and/or the structural arrangement
induced by the flooding of the hold to which the dou- of the double bottom are such to make the above as-
ble bottom belongs to. sumptions inadequate, the shear capacity C of double
The most severe combinations of cargo induced loads bottom is to be calculated by direct calculations.
and flooding loads are to be used, depending on the In calculating the shear strength, the net thickness of
loading conditions included in the loading manual: floors and girders is to be used. The net thickness tnet
– homogeneous loading conditions [mm], is given by:
– non-homogeneous loading conditions t net = t − 2,5 [mm]
– packed cargo conditions (such as steel mill
products) t = thickness [mm], of floors and girders

new E.3
I - Part 1 Section 23 D Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Chapter 1
GL 2012 Cargo and Heavy Cargo Page 23–9

hf

H df

h1,max (rc,min)
h1,min (rc,max)
V

V = Volume of cargo

Fig. 23.4 Flooding head hf of the inner bottom

lower stool transverse bulkhead

floor adjacent floor adjacent to the

to the stool transverse bulkhead
CL

girders

floors

Fig. 23.5 Girders and floors in the double bottom

3.1 Floor shear strength (i.e. that bay which is adjacent to the hopper) Sf2 [kN],
are given by the following expressions:

The floor shear strength in way of the floor panel

adjacent to hoppers Sf1 [kN], and the floor shear
strength in way of the openings in the outmost bay
Chapter 1 Section 23 D Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk I - Part 1
Page 23–10 Cargo and Heavy Cargo GL 2012

τa η2 = 1,15
Sf1 = 10−3 ⋅ A f ⋅
η1 = 1,10, where appropriate reinforcements are
τ fitted
Sf 2 = 10−3 ⋅ A f , h ⋅ a
η2
new E.3.2

Af = sectional area [mm2], of the floor panel adja- 4. Allowable hold loading
cent to hoppers
Calculating the allowable hold loading HL [t], the
Af, h = net sectional area [mm2], of the floor panel in following condition are to be complied with:
way of the openings in the outmost bay (i.e.
HL = the lesser of HL1 and HL2
that bay which is adjacent to the hopper)
τa = allowable shear stress [N/mm2], to be taken ρc V
HL1 =
equal to the lesser of F
HL 2 = HLint
162 ⋅ R eH 0,6 R eH
τa = 0,8
and
 a  3 HLint = max. perm. hold loading for intact condition
 
 t net  F = 1,10 in general
For floors adjacent to the stools or transverse 1,05 for steel mill products
bulkheads, as identified in 3., τa may be taken as
ρc = cargo density [t/m3], for bulk cargoes see 2.1;
R eH
3 for steel products, ρc is to be taken as the
density of steel
a = spacing of stiffening members [mm], of panel V = volume [m3], occupied by cargo assumed
under consideration flattened at a level h1
η1 = 1,10
X
η2 = 1,20 h1 =
ρc ⋅ g
= 1,10, where appropriate reinforcements are
fitted For bulk cargoes, X is the lesser of X1 and X2 given
by:

new E.3.1
Z + ρ ⋅ g ⋅ ( E − hf )
3.2 Girder shear strength X1 = und
ρ
The girder shear strength in way of the girder panel 1 + ( perm − 1)
ρc
adjacent to stools (or transverse bulkheads, if no stool
is fitted) Sg1 [kN], and the girder shear strength in way X2 = Z + ρ ⋅ g ⋅ ( E − h f ⋅ perm )
of the largest opening in the outmost bay (i.e. that bay
which is closer to stool, or transverse bulkhead, if no perm = cargo permeability, (i.e. the ratio between the
stool is fitted) Sg2 [kN], are given by voids within the cargo mass and the volume
occupied by the cargo); need not be taken
τa greater than 0,3.
Sg1 = 10−3 ⋅ A g ⋅
η1 For steel products, X may be taken as X1 using a value
−3 τ for perm according to the type of products (pipes, flat
Sg2 = 10 ⋅ A g,h ⋅ a
η2 bars, coils etc.) harmonized with GL.
Ag = minimum sectional area [mm2], of the girder ρ = 1,025 [t/m3], sea water density
panel adjacent to stools (or transverse bulk- g = 9,81 [m/s2], gravitational acceleration
heads, if no stool is fitted)
E = (nominal ship) immersion [m] for flooded
Ag,h = net sectional area [mm2], of the girder panel hold condition = df – 0,1 H
in way of the largest opening in the outmost
bay (i.e. that bay which is closer to stool, or Z = the lesser of Z1 and Z2:
transverse bulkhead, if no stool is fitted)
τa = allowable shear stress [N/mm2], as given in
3.1
η1 = 1,10
I - Part 1 Section 23 E Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Chapter 1
GL 2012 Cargo and Heavy Cargo Page 23–11

Ch = BDB,h for floors whose shear strength is

Z1 = [kN / m 2 ] given by Sf2, see 3.1
A DB, h
Ce
Z2 = [kN / m 2 ] BDB = breadth of double bottom [m] between hop-
A DB, e
pers, see Fig. 23.6
Ch = shear capacity of the double bottom [kN], as
defined in 3., considering, for each floor, the BDB,h = distance [m] between the two considered
lesser of the shear strengths Sf1 and Sf2 (see openings, see Fig. 23.6
3.1) and, for each girder, the lesser of the
shear strengths Sg1 and Sg2 (see 3.2)
aℓ = spacing [m], of double bottom longitudinals
Ce = shear capacity of the double bottom [kN], as adjacent to hoppers
defined in 3., considering, for each floor, the
shear strength Sf1 (see 3.1) and, for each

new E.4
girder, the lesser of the shear strengths Sg1
and Sg2 (see 3.2)
i=n
A DB, h = ∑ Si ⋅ BDB, i [m 2 ]
i =1
E. Evaluation of Scantlings of Corrugated
i=n Transverse Watertight Bulkheads in Bulk
2
A DB, e = ∑ Si ( BDB − a ℓ ) [m ] Carriers Considering Hold Flooding
i =1

n = number of floors between stools (or trans-

verse bulkheads, if no stool is fitted) 1. Application and definitions
Si = spacing of ith-floor [m]
These requirements apply to all bulk carriers with
BDB,i = BDB – aℓ for floors whose shear strength is
L ≥ 150 m, intended for the carriage of solid bulk
given by Sf1, see 3.1 cargoes having bulk density of 1,0 [t/m3], or above,
BDB,h

CL

BDB

Fig. 23.6 Effective distances BDB and BDB,h for the calculation of shear capacity

with vertically corrugated transverse watertight bulk- each hold, does not exceed 1,20, to be corrected for
heads. different cargo densities.

new F.1
The net thickness tnet is the thickness obtained by
applying the strength criteria given in 4.
2. Load model
The required thickness is obtained by adding the cor-
2.1 General
rosion addition tK, given in 6., to the net thickness tnet.
The loads to be considered as acting on the bulkheads
In this requirement, homogeneous loading condition are those given by the combination of the cargo loads
means a loading condition in which the ratio between with those induced by the flooding of one hold adja-
the highest and the lowest filling ratio, evaluated for cent to the bulkhead under examination. In any case,
Chapter 1 Section 23 E Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk I - Part 1
Page 23–12 Cargo and Heavy Cargo GL 2012

the pressure due to the flooding water alone is to be df is in general:

considered.
– H for the aft transverse corrugated
The most severe combinations of cargo induced loads
bulkhead of the foremost hold
and flooding loads are to be used for the check of the
scantlings of each bulkhead, depending on the loading – 0,9 ⋅ H for the other bulkheads
conditions included in the loading manual:
– homogeneous loading conditions Where the ship is to carry cargoes having bulk density
less than 1,78 t/m³ in non-homogeneous loading con-
– non-homogeneous loading conditions ditions, the following values can be assumed for df:
considering the individual flooding of both loaded and
empty holds. – 0,95 ⋅ H for the aft transverse corrugated
bulkhead of the foremost hold
The specified design load limits for the cargo holds
are to be represented by loading conditions defined in – 0,85 ⋅ H for the other bulkheads
the loading manual.
For ships less than 50 000 tonnes deadweight with
Non-homogeneous part loading conditions associated
Type B freeboard df is:
with multiport loading and unloading operations for
homogeneous loading conditions need not to be con- – 0,95 ⋅ H for the aft transverse corrugated
sidered according to these requirements. bulkhead of the foremost hold
Holds carrying packed cargoes (e.g. steel products) are
to be considered as empty holds for this application. – 0,85 ⋅ H for the other bulkheads
Unless the ship is intended to carry, in non-
Where the ship is to carry cargoes having bulk density
homogeneous conditions, only iron ore or cargo hav-
less than 1,78 [t/m3] in non-homogeneous loading
ing bulk density equal to or greater than 1,78 [t/m3],
conditions, the following values can be assumed:
the maximum mass of cargo which may be carried in
the hold shall also be considered to fill that hold up to – 0,9 ⋅ H for the aft transverse corrugated
the upper deck level at centre line. bulkhead of the foremost hold

new F.2.1
– 0,8 ⋅ H for the other bulkheads
2.2 Bulkhead corrugation flooding head
new F.2.2
The flooding head hf (see Fig. 23.7) is the distance
[m], measured vertically with the ship in the upright
position, from the calculation point to a level located
at a distance df [m], from the baseline.

hf
d1,max (rc,min)
h1,min (rc,max)
h1,max (rc,min)

H df
d1,min (rc,max)

V = Volume of cargo
P = Calculation point

Fig. 23.7 Flooding head hf of a corrugated bulkhead

I - Part 1 Section 23 E Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Chapter 1
GL 2012 Cargo and Heavy Cargo Page 23–13

2.3 Pressure in the non-flooded bulk cargo 2.4 Pressure in the flooded holds
loaded holds
2.4.1 Bulk cargo holds
At each point of the bulkhead, in way of length ℓ ac-
cording to Fig. 23.8 and Fig. 23.9 the pressure pc Two cases are to be considered, depending on the
values of d1 and df.
[kN/m²], is given by:
a) d f ≥ d1
pc = ρc ⋅ g ⋅ h1 ⋅ n
At each point of the bulkhead located at a dis-
ρc = bulk cargo density [t/m³] tance between d1 and df from the baseline, the
pressure pc, f [kN/m2], is given by:
g = 9,81 [m/s2], gravitational acceleration pc, f = ρ ⋅ g ⋅ h f
h1 = vertical distance [m], from the calculation ρ = 1,025 [t/m3], sea water density
point to the horizontal plane corresponding to
the level height of the cargo (see Fig. 23.7), At each point of the bulkhead located at a dis-
located at a distance d1 [m], from the baseline tance lower than d1 from the baseline, the pressure
pc, f [kN/m2], is given by (see also Fig. 23.10):
 γ
n = tan 2  45° −  pc, f = ρ ⋅ g ⋅ hf + [ρc − ρ (1 − perm)] g ⋅ h1 ⋅ n
 2
perm = permeability of cargo, to be taken as 0,3
γ = angle of repose of the cargo, that may gener- for ore (corresponding bulk cargo density
ally be taken as 35° for iron ore and 25° for for iron ore may generally be taken as 3,0
cement. [t/m3]), coal cargoes and for cement (cor-
responding bulk cargo density for cement
The force Fc [kN], acting on a corrugation is given by: may generally be taken as 1,3 [t/m3])

(d1 − h DB − h LS )2 The force Fc,f [kN], acting on a corrugation is

Fc = ρc ⋅ g ⋅ e1 ⋅ n given by:
2
 ( d − d )2
e1 = spacing of corrugations [m], see Fig. 23.8 Fc,f = e1 ⋅ ρ⋅ g ⋅ f 1
 2
hLS = mean height of the lower stool [m], from the ρ ⋅ g ⋅ ( df − d1) + pc,f,le 
inner bottom + ( d1 − hDB − hLS)
2 
hDB = height of the double bottom [m]
pc,f,le = pressure [kN/m2], at the lower end of the

new F.2.3 corrugation
Chapter 1 Section 23 E Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk I - Part 1
Page 23–14 Cargo and Heavy Cargo GL 2012

CL

n = neutral axis of the

corrugations
b

s
tweb
f ³ 55°

aw = max [b;s] e1 tf
an = min [b;s]

Fig. 23.8 Span ℓ of the corrugation (longitudinal section)

see note

Note
For the definition of , the internal end of the upper stool is not to be
taken more than a distance from the deck at the centre line equal to:

- 3 times the depth of corrugations, in general

- 2 times the depth of corrugations, for rectangular stool

Fig. 23.9 Span ℓ of the corrugation (transverse section)

I - Part 1 Section 23 E Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Chapter 1
GL 2012 Cargo and Heavy Cargo Page 23–15

b) df < d1 The resultant force F [kN], acting on a corrugation is

given by:
At each point of the bulkhead located at a dis-
tance between df and d1 from the baseline, the F = Fc, f
pressure pc, f [kN/m2], is given by:

new F.2.5.2
pc,f = ρc ⋅ g ⋅ h1 ⋅ n
3. Bending moment and shear force in the
At each point of the bulkhead located at a dis- bulkhead corrugations
tance lower than df from the baseline, the pres-
sure pc, f [kN/m2], is given by: The bending moment M and the shear force Q in the
bulkhead corrugations are obtained using the formulae
pc,f = ρ ⋅ g ⋅ hf + [ρc ⋅ h1 − ρ (1 − perm) ⋅ hf ] g ⋅ n given in 3.1 and 3.2. The M and Q values are to be
used for the checks in 4.2.
The force Fc, f [kN], acting on a corrugation is

new F.3.1
given by:
3.1 Bending moment
 (d − d )2
Fc,f = e1 ρc ⋅ g ⋅ 1 f ⋅ n The design bending moment M [kN ⋅ m], for the bulk-
 2
head corrugations is given by:
ρc ⋅ g ⋅ (d1 − df ) ⋅ n + pc,f,le  F ⋅ ℓ
+ ( df − hDB − hLS) M =
2  8

new F.2.4.1 F = resultant force [kN], as given in 2.5

ℓ = span of the corrugation [m], to be taken ac-
2.4.2 Pressure in empty holds due to flooding
cording to Fig. 23.8 and 23.9
water alone

new F.3.2
At each point of the bulkhead, the hydrostatic pressure
pf induced by the flooding head hf is to be considered. 3.2 Shear force
The force Ff [kN], acting on a corrugation is given by: The shear force Q [kN], at the lower end of the bulk-
head corrugations is given by:
(d f − h DB − h LS ) 2
Ff = e1 ⋅ ρ ⋅ g Q = 0,8 ⋅ F
2
F = as given in 2.5

new F.2.4.2

new F.3.3
2.5 Resultant pressure and force
4. Strength criteria
2.5.1 Homogeneous loading conditions
4.1 General
At each point of the bulkhead structures, the resultant
pressure p [kN/m2], to be considered for the scantlings The following criteria are applicable to transverse bulk-
of the bulkhead is given by: heads with vertical corrugations, see Fig. 23.8. For
ships of 190 m of length and above, these bulkheads are
p = pc, f − 0,8 ⋅ pc to be fitted with a lower stool, and generally with an
upper stool below deck. For smaller ships, corrugations
may extend from inner bottom to deck. However, if any
The resultant force F [kN], acting on a corrugation is
stools are fitted, they are to comply with the require-
given by:
ments in 4.1.1 and 4.1.2. See also B.8.4.
F = Fc, f − 0,8 ⋅ Fc The corrugation angle φ shown in Fig. 23.8 is not to
be less than 55°.

new F.2.5.1 Requirements for local net plate thickness are given in
4.7.
2.5.2 Non homogeneous loading conditions
In addition, the criteria as given in 4.2 and 4.5 are to
At each point of the bulkhead structures, the resultant be complied with.
pressure p [kN/m2], to be considered for the scantlings
The thicknesses of the lower part of corrugations con-
of the bulkhead is given by:
sidered in the application of 4.2 and 4.3 are to be
p = pc, f maintained for a distance from the inner bottom (if no
Chapter 1 Section 23 E Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk I - Part 1
Page 23–16 Cargo and Heavy Cargo GL 2012

lower stool is fitted) or the top of the lower stool not from the deck level and at hatch side girder. The upper
less than 0,15 ⋅ ℓ. stool is to be properly supported by girders or deep
brackets between the adjacent hatch-end beams.
The thicknesses of the middle part of corrugations as
considered in the application of 4.2 and 4.4 are to be The width of the stool bottom plate is generally to be
maintained to a distance from the deck (if no upper the same as that of the lower stool top plate. The stool
stool is fitted) or the bottom of the upper stool not top of non rectangular stools is to have a width not
greater than 0,3 ⋅ ℓ. less then 2 times the depth of corrugations. The thick-
ness and material of the stool bottom plate are to be
The section modulus of the corrugation in the remain- the same as those of the bulkhead plating below. The
ing upper part of the bulkhead is not to be less than thickness of the lower portion of stool side plating is
75 % of that required for the middle part, corrected for not to be less than 80 % of that required for the upper
different yield strengths. part of the bulkhead plating where the same material is

new F.4.1 used. The thickness of the stool side plating and the
section modulus of the stool side stiffeners is not to be
4.1.1 Lower stool less than required according to Section 11, B. on the
basis of the load model in 2. The ends of stool side
The height of the lower stool is generally to be not less stiffeners are to be attached to brackets at the upper
than 3 times the depth of the corrugations. The thick- and lower ends of the stool. Diaphragms are to be
ness and material of the stool top plate is not to be less fitted inside the stool in line with and effectively at-
than those required for the bulkhead plating above. tached to longitudinal deck girders extending to the
The thickness and material of the upper portion of hatch end coaming girders for effective support of the
vertical or sloping stool side plating within the depth corrugated bulkhead. Scallops in the brackets and
equal to the corrugation flange width from the stool diaphragms in way of the connection to the stool bot-
top is not to be less than the required flange plate tom plate are to be avoided.
thickness and material to meet the bulkhead stiffness
requirement at lower end of corrugation. The thick-
new F.4.1.2
ness of the stool side plating and the section modulus
of the stool side stiffeners is not to be less than those 4.1.3 Alignment
required according to Section 11, B. on the basis of At deck, if no stool is fitted, two transverse reinforced
the load model in 2. The ends of stool side vertical beams are to be fitted in line with the corrugation
stiffeners are to be attached to brackets at the upper flanges.
and lower ends of the stool.
At bottom, if no stool is fitted, the corrugation flanges
The distance d from the edge of the stool top plate to are to be in line with the supporting floors. Corrugated
the surface of the corrugation flange is to be not less bulkhead plating is to be connected to the inner bot-
than the corrugation flange plate thickness, measured tom plating by full penetration welds. The plating of
from the intersection of the outer edge of corrugation supporting floors is to be connected to the inner bot-
flanges and the centre line of the stool top plate, see tom by either full penetration or deep penetration
Fig. 23.12. The stool bottom is to be installed in line welds, see Fig. 23.13. The thickness and material
with double bottom floors and is to have a width not properties of the supporting floors are to be at least
less than 2,5 times the mean depth of the corrugation. equal to those provided for the corrugation flanges.
The stool is to be fitted with diaphragms in line with
the longitudinal double bottom girders for effective Moreover, the cut-outs for connections of the inner
support of the corrugated bulkhead. Scallops in the bottom longitudinals to double bottom floors are to be
brackets and diaphragms in way of the connections to closed by collar plates. The supporting floors are to be
the stool top plate are to be avoided. connected to each other by suitably designed shear
plates.
Where corrugations are cut at the lower stool, corru-
gated bulkhead plating is to be connected to the stool Stool side plating is to align with the corrugation
top plate by full penetration welds. The stool side flanges and stool side vertical stiffeners and their
plating is to be connected to the stool top plate and the brackets in lower stool are to align with the inner
inner bottom plating by either full penetration or deep bottom longitudinals to provide appropriate load trans-
penetration welds, see Fig. 23.13. The supporting mission between these stiffening members. Stool side
floors are to be connected to the inner bottom by ei- plating is not to be knuckled anywhere between the
ther full penetration or deep penetration welds, see inner bottom plating and the stool top.
Fig. 23.13.
new F.4.1.3

new F.4.1.1
4.2 Bending capacity and shear stress τ
4.1.2 Upper stool
The bending capacity is to comply with the following
The upper stool, where fitted, is to have a height gen- relationship:
erally between 2 and 3 times the depth of corruga-
tions. Rectangular stools are to have a height generally
equal to 2 times the depth of corrugations, measured
I - Part 1 Section 23 E Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Chapter 1
GL 2012 Cargo and Heavy Cargo Page 23–17

M ⋅ 103 ing to 4.4, in way of the upper end of shedder

≤ 0,95 or gusset plates, as applicable
0,5 ⋅ Wle ⋅ σa,le + Wm ⋅ σa,m
Q = shear force [kN], as given in 3.2
M = bending moment [kN ⋅ m], as given in 3.1 hg = height [m], of shedders or gusset plates, as
Wle = section modulus of one half pitch corrugation applicable (see Fig. 23.10 and 23.11)
[cm3], at the lower end of corrugations, to be e1 = as given in 2.3
calculated according to 4.3
pg = resultant pressure [kN/m2], as defined in 2.5,
Wm = section modulus of one half pitch corrugation
calculated in way of the middle of the shed-
[cm3], at the mid-span of corrugations, to be ders or gusset plates, as applicable
calculated according to 4.4
σa = allowable stress [N/mm2], as given in 4.5
σa,le = allowable stress [N/mm2], as given in 4.5, for
the lower end of corrugations Stresses τ are obtained by dividing the shear force Q
by the shear area. The shear area is to be reduced in
σa,m = allowable stress [N/mm2], as given in 4.5, for order to account for possible non-perpendicularity
the mid-span of corrugations between the corrugation webs and flanges. In general,
the reduced shear area may be obtained by multi-
In no case is Wm to be taken greater than the lesser of
plying the web sectional area by (sin φ), φ being the
1,15 ⋅ Wle and 1,15 ⋅ W'le for calculation of the bend-
angle between the web and the flange (see Fig. 23.8).
ing capacity, W'le being defined below.
In case shedders plates are fitted which: When calculating the section modulus and the shear
area, the net plate thicknesses are to be used.
– are not knuckled
The section modulus of corrugations are to be calcu-
– are welded to the corrugations and the top of the lated on the basis of the following requirements given
lower stool by one side penetration welds or in 4.3 and 4.4.
equivalent

new F.4.2
– are fitted with a minimum slope of 45° and their
lower edge is in line with the stool side plating 4.3 Section modulus at the lower end of corru-
– have thicknesses not less than 75 % of that pro- gations
vided by the corrugation flange The section modulus is to be calculated with the com-
– and material properties at least equal to those pression flange having an effective flange width, bef,
provided by the flanges not larger than as given in 4.6.1.
or gusset plates are fitted which: If the corrugation webs are not supported by local
brackets below the stool top (or below the inner bot-
– are in combination with shedder plates having tom) in the lower part, the section modulus of the
thickness, material properties and welded connec- corrugations is to be calculated considering the corru-
tions in accordance with the above requirements gation webs 30 % effective.
– have a height not less than half of the flange
width a) Provided that effective shedder plates, as defined
in 4.2, are fitted (see Fig. 23.10), when calculat-
– are fitted in line with the stool side plating ing the section modulus of corrugations at the
– are generally welded to the top of the lower lower end (cross-section 1 in Fig. 23.10), the area
stool by full penetration welds, and to the corru- of flange plates [cm2], may be increased by
gations and shedder plates by one side penetra-
tion welds or equivalent ∆A f = 2,5 ⋅ b ⋅ t f ⋅ t sh [cm 2 ]
– have thickness and material properties at least (not to be taken greater than 2,5 ⋅ b ⋅ tf)
equal to those provided for the flanges
b = width [m], of the corrugation flange, see
the section modulus Wle [cm3], is to be taken not lar- Fig. 23.8
ger than the value W'le [cm3], given by:
tsh = net shedder plate thickness [mm]
Q ⋅ h g − 0,5 ⋅ h g2 ⋅ e1 ⋅ pg
Wle' = Wg + 103 tf = net flange thickness [mm]
σa
Wg = section modulus of one half pitch corrugation
[cm3], of the corrugations calculated, accord-
Chapter 1 Section 23 E Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk I - Part 1
Page 23–18 Cargo and Heavy Cargo GL 2012

a) Symmetric shedder plates b) Asymmetric shedder plates

shedder shedder
hg plate hg plate

1 1
lower lower
stool stool

Fig. 23.10 Shedder plates

a) Symmetric gusset / shedder plates b) Asymmetric gusset / shedder plates

gusset gusset
plate plate

hg hg =
1
=
1 gusset
lower
lower
hg

lower

Fig. 23.11 Gusset plates and shedder plates

corrugation flange corrugation flange

tf tf tf tf

stool top plate d stool top plate

d d

d
d ³ tf
tf = as-built flange thickness

Fig. 23.12 Excess end d of the stool top plate

I - Part 1 Section 23 E Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Chapter 1
GL 2012 Cargo and Heavy Cargo Page 23–19

t t

f f
a
a a

Root face f : 3 mm to t/3 mm

Groove angle a : 40° to 60°

Fig. 23.13 Connection by deep penetration welds

Fig. 23.14 Single and double side skin bulk carrier

b) Provided that effective gusset plates, as defined

c) If the corrugation webs are welded to a sloping
in 4.2, are fitted (see Fig. 23.11), when calculat-
stool top plate which has an angle not less than
ing the section modulus of corrugations at the
45° with the horizontal plane, the section
lower end (cross-section 1 in Fig. 23.11), the modulus of the corrugations may be calculated
area of flange plates [cm²], may be increased by considering the corrugation webs fully effective.
∆A f = 7 ⋅ h g ⋅ t f [cm 2 ]

hg = height of gusset plate [m], see Fig. In case effective gusset plates are fitted, when
calculating the section modulus of corrugations
23.11, not to be taken greater than: the area of flange plates may be increased as
10 specified in b) above. No credit can be given to
hg = a gu [m] shedder plates only.
7
agu = width of the gusset plates [m]
For angles less than 45°, the effectiveness of the
= 2 e1 – b web may be obtained by linear interpolation be-
tween 30 % for 0° and 100 % for 45°.
tf = net flange thickness [mm], based on the
as built condition

new F.4.3
Chapter 1 Section 23 F Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk I - Part 1
Page 23–20 Cargo and Heavy Cargo GL 2012

4.4 Section modulus of corrugations at cross- p = resultant pressure [kN/m2], as defined in 2.5, at
sections other than the lower end the bottom of each strake of plating; in all cases,
the net thickness of the lowest strake is to be de-
The section modulus is to be calculated with the cor- termined using the resultant pressure at the top
rugation webs considered effective and the compres- of the lower stool, or at the inner bottom, if no
sion flange having an effective flange width, bef, not lower stool is fitted or at the top of shedders, if
larger than as given in 4.6.1. shedder or gusset/shedder plates are fitted

new F.4.4 For built-up corrugation bulkheads, when the thick-
nesses of the flange and web are different, the net
4.5 Allowable stress check
thickness of the narrower plating is to be not less than
tnet,n [mm], given by:
The normal and shear stresses σ and τ are not to ex-
ceed the allowable values σa and τa [N/mm2], given 1, 05 ⋅ p
by: t net,n = 14,9 ⋅ a n
R eH
σa = R eH an = the width [m], of the narrower plating, see
Fig. 23.8
τa = 0,5 ⋅ R eH
The net thickness of the wider plating [mm], is not to
be taken less than the maximum of the following val-

new F.4.5 ues tw1 and tw2:

4.6 Effective compression flange width and 1, 05 ⋅ p

t w1 = 14,9 ⋅ a w
shear buckling check R eH

4.6.1 Effective width of the compression flange 440 ⋅ a 2w ⋅ 1, 05 ⋅ p 2

of corrugations tw2 = − t np
R eH
The effective width bef [m], of the corrugation flange where tnp ≤ actual net thickness of the narrower plat-
is calculated according to Section 3, F. ing and not to be greater than tw1.

new F.4.6.1
new F.4.7

5. Shedder and gussed plates

4.6.2 Shear buckling
The thickness and stiffening of effective gusset and
The buckling check for the web plates at the corruga- shedder plates, as defined in 4.3, is to determined
tion ends is to be performed according to Section 3, F. according to Section 12, B. on the basis of the load
The buckling factor is to be taken as follows: model in 2.

new F.5
K = 6,34 ⋅ 3
6. Corrosion addition and steel renewal
The shear stress τ has to be taken according to 4.2 and The corrosion addition tK is to be taken equal to
the safety factor S is 1,05. 3,5 mm.

new F.6

new F.4.6.2

4.7 Local net plate thickness

F. Harmonised Notations and Corresponding
Design Loading Conditions for Bulk Car-
The bulkhead local net plate thickness tnet [mm], is
riers
given by:
1. Application
1, 05 ⋅ p
t net = 14,9 ⋅ a w 1.1 These requirements are applicable to bulk car-
R eH
riers as defined in B.1. having a length L of 150 m or
above. The consideration of the following requirements
aw = plate width [m], to be taken equal to the is recommended for ships having a length L < 150 m.
width of the corrugation flange or web,
new G.1.1
whichever is the greater, see Fig. 23.8
I - Part 1 Section 23 F Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Chapter 1
GL 2012 Cargo and Heavy Cargo Page 23–21

1.2 The loading conditions listed under 3. are to multiple ports in accordance with the conditions
be checked regarding longitudinal strength as required specified in 5.3
by Section 5, local strength, capacity and disposition of
– {holds, a, b, ... may be empty} for Notation
ballast tanks and stability. The loading conditions listed
under 4. are to be checked regarding local strength. BC-A

new G.2.2

new G.1.2

1.3 For the loading conditions given in this docu- 3. Design loading conditions (General)
ment, maximum draught is to be taken as moulded
summer load line draught. 3.1 BC-C

new G.1.3 Homogeneous cargo loaded condition where the cargo
density corresponds to all cargo holds, including hatch-
1.4 These requirement are not intended to pre- ways, being 100 % full at maximum draught with all
vent any other loading conditions to be included in the ballast tanks empty.
loading manual for which calculations are to be sub-
new G.3.1
mitted see Section 5, nor is it intended to replace in
any way the required loading manual/instrument. 3.2 BC-B

new G.1.4 As required for BC-C, plus:
1.5 A bulk carrier may in actual operation be Homogeneous cargo loaded condition with cargo
loaded differently from the design loading conditions density 3,0 tonnes/m3, and the same filling ratio (cargo
specified in the loading manual, provided limitations mass/hold cubic capacity) in all cargo holds at maxi-
for longitudinal and local strength as defined in the mum draught with all ballast tanks empty.
loading manual and loading instrument onboard and In cases where the cargo density applied for this de-
applicable stability requirements are not exceeded. sign loading condition is less than 3,0 tonnes/m3, the

new G.1.5 maximum density of the cargo that the vessel is al-
lowed to carry is to be indicated with the additional
2. Harmonized notations and annotations Notation {maximum cargo density ... t/ m3}.

new G.3.2
2.1 Notations
Bulk Carriers are to be assigned one of the following 3.3 BC-A
notations. As required for BC-B, plus:
BC-C: for bulk carriers designed to carry dry bulk At least one cargo loaded condition with specified
cargoes of cargo density less than 1,0 t/m3. holds empty, with cargo density 3,0 tonnes/m3, and
the same filling ratio (cargo mass/hold cubic capacity)
BC-B: for bulk carriers designed to carry dry bulk in all loaded cargo holds at maximum draught with all
cargoes of cargo density of 1,0 t/m3 and above ballast tanks empty.
with all cargo holds loaded in addition to BC-
C conditions. The combination of specified empty holds shall be
indicated with the additional Notation {holds a, b, ...
BC-A: for bulk carriers designed to carry dry bulk may be empty}.
cargoes of cargo density of 1,0 t/m3 and above
In such cases where the design cargo density applied
with specified holds empty at maximum
is less than 3,0 tonnes/m3, the maximum density of the
draught in addition to BC-B conditions.
cargo that the vessel is allowed to carry shall be indi-

new G.2.1 cated within the additional Notation, e.g. {holds a, b,
... may be empty; maximum cargo density t/m3}.
2.2 Additional Notations
new G.3.3
The following additional Notations are to be provided
giving further detailed description of limitations to be 3.4 Ballast conditions (applicable to all Nota-
observed during operation as a consequence of the tions)
design loading condition applied during the design in
the following cases: 3.4.1 Ballast tank capacity and disposition

– {maximum cargo density ... t/m3} for Nota- All bulk carriers are to have ballast tanks of sufficient
tions BC-A and BC-B if the maximum cargo capacity and so disposed to at least fulfill the following
density is less than 3,0 tonnes/m3 requirements for normal and heavy ballast condition:

– {no MP} for all Notations when the vessel has Normal ballast condition for the purpose of these
not been designed for loading and unloading in requirements is a ballast (no cargo) condition where:
Chapter 1 Section 23 F Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk I - Part 1
Page 23–22 Cargo and Heavy Cargo GL 2012

– the ballast tanks may be full, partially full or – the longitudinal strength requirements according
empty. Where partially full option is exercised, to Section 5, B. are to be met for the condition
the conditions in Section 5, A.4.4.1 are to be of 3.4.1 for heavy ballast
complied with
– in addition, the longitudinal strength require-
– any cargo hold or holds adapted for the carriage ments according to Section 5, B. are to be met
of water ballast at sea are to be empty with all ballast tanks 100 % full and any one
cargo hold adapted for the carriage of water bal-
– the propeller is to be fully immersed last at sea, where provided, 100 % full
– the trim is to be by the stern and is not to exceed – where more than one hold is adapted and desig-
0,015 L, where L is the length between perpen- nated for the carriage of water ballast at sea, it
diculars of the ship will not be required that two or more holds be
assumed 100 % full simultaneously in the longi-
In the assessment of the propeller immersion and trim,
tudinal strength assessment, unless such condi-
the draughts at the forward and after perpendiculars tions are expected in the heavy ballast condition.
may be used. Unless each hold is individually investigated,
Heavy ballast condition for the purpose of these re- the designated heavy ballast hold and any/all re-
quirements is a ballast (no cargo) condition where: strictions for the use of other ballast hold(s) are
to be indicated in the loading manual.
– the ballast tanks may be full, partially full or
empty. Where partially full option is exercised,
new G.3.4.2
the conditions in Section 5, A.4.4.1 are to be
complied with, 4. Departure and arrival conditions
– at least one cargo hold adapted for carriage of Unless otherwise specified, each of the design loading
water ballast at sea, where required or provided, conditions defined in 3.1 to 3.4 is to be investigated for
is to be full, the arrival and departure conditions as defined below.
– the propeller immersion I/D is to be at least Departure condition: with bunker tanks not less than
60 % where: 95 % full and other consum-
ables 100 %
– I = the distance from propeller centreline
to the waterline Arrival condition: with 10 % of consumables

– D = propeller diameter, and
new G.4

– the trim is to be by the stern and is not to exceed 5. Design loading conditions (for local
0,015 L, where L is the length between perpen- strength)
diculars of the ship,
– the moulded forward draught in the heavy bal- 5.1 Definitions
last condition is not to be less than the smaller of The maximum allowable or minimum required cargo
0,03 L or 8 m. mass in a cargo hold, or in two adjacently loaded holds,

new G.3.4.1 is related to the net load on the double bottom. The net
load on the double bottom is a function of draft, cargo
3.4.2 Strength requirements mass in the cargo hold, as well as the mass of fuel oil
and ballast water contained in double bottom tanks.
All bulk carriers are to meet the following strength
requirements: The following definitions apply:
MH: the actual cargo mass in a cargo hold corre-
Normal ballast condition:
sponding to a homogeneously loaded condi-
– the structures of bottom forward are to be tion at maximum draught
strengthened in accordance with the GL Rules
against slamming for the condition at the light- MFull: the cargo mass in a cargo hold corresponding
est forward draught, to cargo with virtual density (homogeneous
mass/hold cubic capacity, minimum 1,0 tonne/
– the longitudinal strength requirements according m3) filled to the top of the hatch coaming.
to Section 5, B. are to be met for the condition MFull is in no case to be less than MH.
of 3.4.1 for normal ballast, and
MHD: the maximum cargo mass allowed to be car-
– in addition, the longitudinal strength require- ried in a cargo hold according to design load-
ments of according to Section 5, B. are to be met ing condition(s) with specified holds empty at
with all ballast tanks 100 % full. maximum draught
Heavy ballast condition:
new G.5.1
I - Part 1 Section 23 F Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Chapter 1
GL 2012 Cargo and Heavy Cargo Page 23–23

5.2 General conditions applicable for all Nota-
new G.5.4.1

tions
5.4.2 Cargo holds, which are intended to be loaded
5.2.1 Any cargo hold is to be capable of carrying with high density cargo, are to be capable of carrying
MFull with fuel oil tanks in double bottom in way of MHD plus 10 % of MH, with fuel oil tanks in the double
the cargo hold, if any, being 100 % full and ballast bottom in way of the cargo hold, if any, being 100 %
water tanks in the double bottom in way of the cargo full and ballast water tanks in the double bottom being
hold being empty, at maximum draught. empty in way of the cargo hold, at maximum draught.

new G.5.2.1 In operation the maximum allowable cargo mass shall
be limited to MHD.
5.2.2 Any cargo hold is to be capable of carrying
minimum 50 % of MH, with all double bottom tanks in
new G.5.4.2
way of the cargo hold being empty, at maximum draught.
5.4.3 Any two adjacent cargo holds which accord-

new G.5.2.2 ing to a design loading condition may be loaded with
the next holds being empty, are to be capable of carry-
5.2.3 Any cargo hold is to be capable of being
empty, with all double bottom tanks in way of the car- ing 10 % of MH in each hold in addition to the maxi-
go hold being empty, at the deepest ballast draught. mum cargo load according to that design loading con-
dition, with fuel oil tanks in the double bottom in way

new G.5.2.3 of the cargo hold, if any, being 100 % full and ballast
water tanks in the double bottom in way of the cargo
5.3 Condition applicable for all Notations, hold being empty, at maximum draught.
except when Notation {no MP} is assigned
In operation the maximum allowable mass shall be
5.3.1 Any cargo hold is to be capable of carrying limited to the maximum cargo load according to the
MFull with fuel oil tanks in double bottom in way of design loading conditions.
the cargo hold, if any, being 100 % full and ballast

new G.5.4.3
water tanks in the double bottom in way of the cargo
hold being empty, at 67 % of maximum draught.
5.5 Additional conditions applicable for bal-

new G.5.3.1 last hold(s) only
5.3.2 Any cargo hold is to be capable of being Cargo holds, which are designed as ballast water
empty with all double bottom tanks in way of the holds, are to be capable of being 100 % full of ballast
cargo hold being empty, at 83 % of maximum draught. water including hatchways, with all double bottom

new G.5.3.2 tanks in way of the cargo hold being 100 % full, at any
heavy ballast draught. For ballast holds adjacent to
5.3.3 Any two adjacent cargo holds are to be capa- topside wing, hopper and double bottom tanks, it shall
ble of carrying MFull with fuel oil tanks in double be strengthwise acceptable that the ballast holds are
bottom in way of the cargo hold, if any, being 100 % filled when the topside wing, hopper and double bot-
full and ballast water tanks in the double bottom in tom tanks are empty.
way of the cargo hold being empty, at 67 % of the
new G.5.5
maximum draught. This requirement to the mass of
cargo and fuel oil in double bottom tanks in way of the 5.6 Additional conditions applicable during
cargo hold applies also to the condition where the loading and unloading in harbour only
adjacent hold is fitted with ballast, if applicable.
5.6.1 Any single cargo hold is to be capable of

new G.5.3.3 holding the maximum allowable seagoing mass at
67 % of maximum draught, in harbour condition.
5.3.4 Any two adjacent cargo holds are to be capa-
ble of being empty, with all double bottom tanks in
new G.5.6.1
way of the cargo hold being empty, at 75 % of maxi-
mum draught. 5.6.2 Any two adjacent cargo holds are to be capa-
ble of carrying MFull ,with fuel oil tanks in the double

new G.5.3.4
bottom in way of the cargo hold, if any, being 100 %
full and ballast water tanks in the double bottom in
5.4 Additional conditions applicable for BC-A way of the cargo hold being empty, at 67 % of maxi-
Notation only mum draught, in harbour condition.
5.4.1 Cargo holds, which are intended to be empty
new G.5.6.2
at maximum draught, are to be capable of being empty
with all double bottom tanks in way of the cargo hold 5.6.3 At reduced draught during loading and
also being empty. unloading in harbour, the maximum allowable mass in
Chapter 1 Section 23 H Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk I - Part 1
Page 23–24 Cargo and Heavy Cargo GL 2012

a cargo hold may be increased by 15 % of the maxi- B.1.1.4) and hatch cover stoppers (see Section 17,
mum mass allowed at the maximum draught in sea- B.4.7) of the foremost cargo hold, the distances be-
going condition, but shall not exceed the mass allowed tween all points of the aft edge of the forecastle deck
at maximum draught in the sea-going condition. and the hatch coaming plate, ℓF [m], are to comply
The minimum required mass may be reduced by the with the following (see Fig. 23.15):
same amount.
ℓ F = 5 H F − Hc [m]

new G.5.6.3

5.7 Hold mass curves A breakwater is not to be fitted on the forecastle deck
for the purpose of protecting the hatch coaming or
Based on the design loading criteria for local strength, hatch covers. If fitted for other purposes, the distance
as given in 5.2 to 5.6 (except 5.5.1) above, hold mass between its upper edge at centre line and the aft edge
curves are to be included in the loading manual and of the forecastle deck, ℓB [m], is to comply with the
the loading instrument, showing maximum allowable following (see Fig. 23.15):
and minimum required mass as a function of draught
in sea-going condition as well as during loading and ℓ B ≥ 2,75 ⋅ H B [m]
unloading in harbour, see B.10.
At other draughts than those specified in the design HB = is the height of the breakwater above the
loading conditions above, the maximum allowable and forecastle.
minimum required mass is to be adjusted for the
change in buoyancy acting on the bottom. Change in
new H.2
buoyancy is to be calculated using water plane area at
c cd · c
each draught. n4

Hold mass curves for each single hold, as well as for coil coil n2 coil
any two adjacent holds, are to be included.
dc

dunnages n3 n3

new G.5.7

stiffener

c /n3
G. Fitting of a Forecastle for Bulk Carriers,
floor c floor
Ore Carriers and Combination Carriers
b

1. Application
Fig. 23.15 Dimensions of the forecastle
All bulk carriers, ore carriers and combination carriers
are to be fitted with an enclosed forecastle on the
freeboard deck.
The structural arrangements and scantlings of the H. Transport of Steel Coils in Multi-Purpose
forecastle are to comply with the requirements of Dry Cargo Ships
Section 16.

new H.1 1. General

1.1 Symbols
2. Dimensions
a = shorter side of plate field (distance of longi-
The forecastle is to be located on the freeboard deck
tudinals) [m]
with its aft bulkhead fitted in way or aft of the forward
bulkhead of the foremost hold (see Fig. 23.15). ay = transverse acceleration for the considered load
The forecastle height, HF [m], above the main deck is case acc. Section 4, E. As first approximation
not to be less than the greater of: GM = 0, 24 ⋅ B and a center of gravity of the
– the standard height of a superstructure as speci- steel coil loading of z = hDB + (1 + 0,866 (n1–1))
fied in the ICLL, or ⋅ dc/2 can be used to determine ay.
– Hc + 0,5 [m]
av = acceleration addition acc. Section 4, C.
Hc = height of the forward transverse hatch coam-
ing of cargo hold No. 1 [m] BH = breadth of cargo hold [m]

In order to use the reduced design loads for the for- b = longer side of plate field (distance trans-
ward transverse hatch coaming (see Section 17, verses) [m]
I - Part 1 Section 23 H Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Chapter 1
GL 2012 Cargo and Heavy Cargo Page 23–25

cd = coefficient for the distance of steel coils in 1.4 Sufficient safety against buckling has to be
ship's longitudinal direction proofed acc. to Section 3, F. for floors and girders of
bottom and side structure.
 0,3 
= min  0, 2; 
new Section 3, D.1.1
 ℓc 
1.5 The "Code of Safe Practice for Cargo Stowage
dc = diameter of steel coils [m] und Securing" (IMO Res. A714(17) as amended) has to
be observed for the stowage of steel coils in seagoing
hDB = height of double bottom [m] ships. Especially sufficient supporting of coils by means
of dunnages laid athwartships has to be observed.
k = material coefficient acc. to Section 2, B.

new I.1.3
ℓc = length of steel coils [m]
2. Inner bottom plating
tk = corrosion addition acc. to Section 3, K. The plate thickness of inner bottom is not to be less than:
W = mass of one steel coil [kg]
P
t = 1,15 ⋅ K1 + t k [mm]
µ = coefficient of friction σpl

= 0,3 in general
1, 7 ⋅ a ⋅ b ⋅ K 2 − 0, 73 ⋅ a 2 ⋅ K 22 − (b − c)2
K1 =
σLI = maximum design hull girder bending stress in 2 ⋅ c ( 2 ⋅ a + 2 ⋅ b ⋅ K2 )
the inner bottom according to Section 5, D.1.
[N/mm2] 2 2 2
a a b  c
K2 = − +   + 1,37   1 − b  + 2,33
σLL = maximum design hull girder bending stress in b b a  
the longitudinal bulkhead according to Sec-
tion 5, D.1. [N/mm2] c = distance between outermost patch loads in a
plate field [m]
σperm = permissible design stress [N/mm2]
ℓc
= ( n 2 − 1) + cd ⋅ ℓ c ( n 4 − 1)
 L  230 n3
=  0,8 +  for L < 90 m
 450  k n1 = number of tiers of coils
230 = 1,4 for one tier, secured with key coils
= for L ≥ 90 m
k n2 = number of patch loads per plate field, see also
τL = maximum design shear stress due to longitu- Fig. 23.16, whereat n2 has to be rounded up
dinal hull girder bending according to Section to the next integer
5, D.1. [N/mm2]
 b 
= n 3  − cd ( n 4 − 1)  , in general
Θ = design roll angle  ℓc 
= 30 deg ℓc
= n 3 ⋅ n 4 for ( n 3 − 1) < b − (1 + cd ) ⋅ ℓ c ( n 4 − 1)

new A.3 n3

1.2 The requirements of this section are valid for n3 = number of dunnages per coil, see Fig. 23.16
ships with longitudinal framing and vertical longitudi- n4 = number of coils per plate field, see Fig.
nal bulkheads. Ships with other construction are to be 23.16, whereat n4 has to be rounded up to the
considered separately.
next integer

new I.1.1
b
=
1.3 The equations for calculation of the distance ( d ) ⋅ ℓc
1 + c
between the outermost patch loads within a plate field
c, the number of steel coils within one row athwart- P = Fp (1 + a v ) [N]
ships n5 and the number of tiers n1 in 2. and 3. may be
used, if a direct determination based on stowing ar- Fp = mass force acting on one plate field [N]
rangement plans is not possible.
W ⋅ n1 ⋅ n 2
= 9,81

new I.1.2 n3
Chapter 1 Section 23 H Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk I - Part 1
Page 23–26 Cargo and Heavy Cargo GL 2012

σpl = σ2perm − 0, 786 ⋅ σ perm ⋅ σ LI − 3 τ2L − 0,062 σ LI

new I.2

c cd · c
n4

Stahlblechrolle Stahlblechrollen Stahlblechrolle

2
dc

Stauhölzer n3 n3

Steife

c /n3

Bodenwrange c Bodenwrange
b

Fig. 23.16 Exemplary arrangement for determination of n2, n3 and n4

Note
n6 = 0 for n1 = 1
As a first approximation σLI and τL may be taken as
= number of key coils for n1 = 1,4
follows:
= BH d c − 1 for n1 = 2
12,6 L
σ LI = [ N / mm 2 ] for L < 90 m
k = 2 ⋅ BH d c − 3 for n1 = 3
120 BH/dc has to be rounded up to the next integer for
= [ N / mm 2 ] for L ≥ 90 m determination of n5 and n6.
k
τL = 0 [ N / mm 2 ] σpl = σ2perm − 0, 786 ⋅ σperm ⋅ σ LL − 3 τ2L − 0, 062 σ LL

new I.2 Note
For sloping plates (e.g. Hopper plates) additional
3. Plating of longitudinal bulkhead forces have to be observed for the calculation of P*.
Furthermore the force components rectangular to the
The plate thickness of the longitudinal bulkhead at plate have to be determined.
least to a height of one frame distance above the high-
est possible contact line with the steel coil loading is
new I.3
not to be less than:
Note
P*
t = K1 + tk [mm] As a first approximation σLI and τL may be taken as
σpl follows:
K1 = see 2. σ LL = 0,76 ⋅σ LI
P *
= Fp* ( a y − µ ⋅ cos Θ ) [N] 55
τL = [ N / mm 2 ]
W ⋅ n2 ⋅ n5 k
Fp* = 9,81 [N]
n3 σ LI = see 2.
n2, n3 = see 2.
new I.3 Note
n5 = number of coils in one row athwardships
BH
= + n6
dc
I - Part 1 Section 23 H Bulk Carriers, Ore Carriers and Ships with Strengthenings for Bulk Chapter 1
GL 2012 Cargo and Heavy Cargo Page 23–27

Side structure:
4. Scantlings of longitudinal stiffeners Acting mass per dunnage = Fp* /n2, accelerated by
(ay – µ ⋅ cosΘ), see also 3.
4.1 Analysis model
The scantlings of the longitudinals of inner bottom The stresses caused by global ship deflections have to
and side structure have to be determined by using be superposed.
simple beam theory.
new I.4.2
For this purpose the beams have to be loaded accord- 4.3 Permissible stresses
ing to the possible load combinations for the coils. The permissible stresses of Section 9, B.3. have to be
observed.
Boundary conditions for the beam model have to be
selected with respect to the intersection details at The permissible shear stress is 100/k [N/mm2].
floors and web frames.
Sufficient shear area at intersections between longitu-

new I.4.1 dinals and floors or web frames has to be considered.
Furthermore sufficient strength of heel stiffeners has
4.2 Loads to be observed.

The forces have to be determined with respect to
new I.4.3

the expected load combinations of coils. If this is
notknown, estimations according to 2. and 3. can be 4.4 Strengthening of side structure
made as follows: Appropriate reinforcement has to be arranged in way
of the contact line of the steel coils with the longitudi-
Inner bottom: nal bulkhead e.g. a longitudinal stiffener or stringer.
Acting mass per dunnage = Fp/n2, accelerated by av
new I.4.4
according to Section 4, C.1.
I - Part 1 Section 24 A Oil Tankers Chapter 1
GL 2012 Page 24–1

Section 24

Oil Tankers

A. General
Note
1. Scope 1. In accordance with the provisions of MARPOL
73/78, Annex II the carriage in bulk of category
1.1 The following requirements apply to tankers Z products is permitted only on vessels holding
which are intended to carry oil in bulk having a flash- an "International Pollution Prevention Certifi-
point (closed cup test) not exceeding 60 °C and whose cate for the Carriage of Noxious Liquid Sub-
Reid vapour pressure is below that of atmospheric
stances in Bulk" issued by the Flag Administra-
pressure and other liquid products having a similar fire
hazard. tion.
2. The petrochemicals listed in the list of products

new A.1.4 of the IBC-Code, Chapter 17, and products of
Unless specially mentioned in this Section the re- similar hazard are not subject to the provisions
quirements of Sections 1 to 22 apply. of this Section.

new A.1.3
new A.1.5 Note

For double hull oil tankers and product tankers with 1.5 The requirements of this Section include the
L ≥ 150 m the IACS Common Structural Rules for provisions of Chapter II-2 of SOLAS 74 applicable to
Double Hull Oil Tankers are applicable in lieu of B. to tankers as far as provisions affecting the lay-out and
F. structural design of the vessels are concerned.

I-0, Section 2, Table 2.6
For the remaining fire safety measures of the above
mentioned provisions, see Section 22, F. and the GL
1.2 For the purpose of this Section "oil" means Rules for Machinery Installations (I-1-2), Section 12
petroleum in any form including crude oil, refined and 15.
products, sludge and oil refuse (see also Product List 1
at the end of this Section).
new A.2.2

new A.3
1.6 Requirements for ships intended to carry dry
1.3 For the purpose of this Section "crude oil" cargo or oil in bulk see G.
means any liquid hydrocarbon mixture occurring natu-

new A.1.6
rally in the earth whether or not treated to render it
suitable for transportation and includes:
1.7 For tankers intended to carry liquids in bulk
– crude oil from which certain distillate fractions having a flashpoint (closed cup test) above 60 °C only,
may have been removed, and the requirements of this Section concerning safety,
e.g. as per 4.4, 4.5, 9. etc., need not be complied with.
– crude oil to which certain distillate fractions
may have been added Where, however, these products are heated to a tem-

new A.3 perature above 15 °C below their flashpoint the ves-
sels will be specially considered.
1.4 Products listed in the Product List 2 (at the
new A.1.7
end of this Section) are permitted to be carried in
tankers complying with the requirements of this Sec-
tion. Products whose Reid vapour pressure is above 1.8 Where cargo is intended to be heated Section
that of atmospheric pressure may only be carried 12, A.6. is also to be observed.
where the cargo tank vents are fitted with pres-

new A.2.1
sure/vacuum relief valves (see the GL Rules for Ma-
chinery Installations (I-1-2), Section 15) and the tanks
have been dimensioned for the set pressure of the 1.9 Oil or other flammable liquids are not permit-
pressure relief valves. ted to be carried in the fore- or afterpeak.

new A.1.5
new B.1

Chapter 1 Section 24 A Oil Tankers I - Part 1
Page 24–2 GL 2012

Note "Not suitable for cargo

It is assumed that the provisions of Annex I and, as far with flashpoint ≤ 60 °C".
as applicable, of Annex II of MARPOL 73/78 will be
complied with.
I-0, Section 2, Table 2.6
Upon application a declaration confirming the com-
pliance with the provisions of MARPOL 73/78 will be 2.5 Where special structural measures (separation
issued. of piping, tank coating etc.) permit simultaneous car-
riage of various oils and oil products, the following
Tankers not complying with the Annex I provisions remark may be entered in the Certificate:
will not be assigned the notation OIL TANKER or
PRODUCT TANKER. "Suitable for the carriage of various oil products".
For a type "A" ship, if over 150 m length, to which a
I-0, Section 2, Table 2.6
freeboard less than type "B" has been assigned the
ICLL Regulation 27.3 has to be considered. 2.6 Where the cargo tanks are not segregated

new A.1.7 Note from other spaces in fore and aft ship (see 4.3.6) the
following remark will be entered in the Certificate:
2. Character of Classification "No cofferdams at the forward and/or aft ends".
2.1 Tankers, built in accordance with the re-
quirements of this Section will have the following 3. Cargo tank arrangement
Notations affixed to their Character of Classification:
OIL TANKER if engaged in the trade of carrying 3.1 General
"oil" as defined in 1.2 or PRODUCT TANKER if
engaged in the trade of carrying oil other than "crude
3.1.1 Every oil tanker of 600 tdw and above shall
oil" as defined in 1.3.
comply with the double hull requirements of MAR-

I-0, Section 2, Table 2.5 POL 73/78, Annex I, Reg. 19.
Oil tankers or product tankers will be assigned the
new B.2.1.1
symbol  for characterizing proof of damage stability
according to MARPOL 73/78 Annex I. The following 3.1.2 Tanks or spaces within the double hull re-
data will be entered into an appendix to the Certificate: quired in accordance with the provisions of 3.2 and 3.3
– code for the specification of the proof of damage are not to be used for the carriage of cargo and fuel oil.
stability according to the GL Rules for Classifi-

new B.2.1.2
cation and Surveys (I-0), Section 2, C.2.4.

I-0, Section 2, Table 2.1 3.1.3 For access to spaces in the cargo area A.13. is
to be observed.
2.2 Ships intended to alternatively carry dry car-
go or liquids in bulk having a flashpoint (closed cup
new B.2.1.3
test) not exceeding 60 °C may have one of the follow-
ing Notations affixed to their Character of Classifi- 3.1.4 Concerning the definition of "deadweight"
cation: BC / OIL TANKER, ORE CARRIER / OIL (tdw) reference is made to MARPOL 73/78, Annex I,
TANKER, ORE CARRIER / PRODUCT TANKER. Reg. 1.23
The requirements specified in G. are to be observed.
new B.2.1.4

new I-0, Section 2, Table 2.5
Note
2.3 Tankers intended to carry liquids of different
properties and presenting hazards different from the The aggregate capacity of wing tanks, double bottom
criteria of liquids mentioned in 1.2 will be specially tanks, forepeak tanks and afterpeak tanks shall not be
considered as "tankers for special cargoes". These less than the capacity of segregated ballast tanks
tankers may have the notation: SPECIAL TANKER, necessary to meet the requirements of MARPOL
ASPHALT TANKER, EDIBLE OIL TANKER, 73/78, Annex I, Regulation 18. Wing tanks, spaces and
WINE TANKER, etc. affixed to their Character of double bottom tanks used to meet the requirements of
Classification. MARPOL 73/78, Annex I, Regulation 18 shall be
located as uniformly as practicable along the cargo

new I-0, Section 2, Table 2.5 tank length. For inerting, ventilation and gas meas-
2.4 Where it is intended to carry liquids having a urement see the GL Rules for Machinery Installations
flashpoint (closed cup test) above 60 °C only, the (I-1-2), Section 15.
following remark will be entered in the Certificate:

new B.2.1.4 Note
I - Part 1 Section 24 A Oil Tankers Chapter 1
GL 2012 Page 24–3

3.2 Double hull requirements for oil tankers of 3.2.5 Alternative cargo tank arrangements
5 000 tdw and above
Double bottom tanks or spaces as required above may
be dispensed with, if the provisions of MARPOL
3.2.1 The entire cargo tank length is to be protected
73/78, Annex I, Reg. 19.4 or 19.5 are complied with.
by a double side (wing tanks or spaces) and double
bottom tanks or spaces as outlined in the following
new B.2.2.5
paragraphs.
3.2.6 Double bottom in pump room

new B.2.2.1
The cargo pump room is to be provided with a double
bottom, the distance h of which above the ship's base
3.2.2 Double side line is not less than the distances required in 3.2.3.
Wing tanks or spaces are to extend either for the full
new B.2.2.6
depth of the ship's side or from the top of the double
bottom to the uppermost deck, disregarding a rounded Note
gunwale where fitted. They are to be arranged such
For pump rooms, the bottom plate of which is above
that the cargo tanks are located inboard of the
this minimum height, see 22.3 of MARPOL 73/78,
moulded line of the side shell plating, nowhere less
Annex I.
than the distance w which is measured at every cross-
section at right angles to the side shell as specified
new B.2.2.6 Note
below:
3.3 Double hull requirements for oil tankers of
tdw less than 5 000 tdw
w = 0,5 + [m] or
20 000
3.3.1 Double bottom
= 2, 0 m, whichever is lesser
Oil tankers of less than 5 000 tdw are at least to be
w min = 1, 0 m fitted with double bottom tanks or spaces having such
a depth that the distance h specified in 3.2.3 complies

new B.2.2.2 with the following:

B
3.2.3 Double bottom h = [ m]
15
At any cross-section the depth of each double bottom h min = 0, 76 m
tank or space is to be such that the distance h between
the bottom of the cargo tanks and the moulded line of In the turn of bilge area and at locations without a
the bottom shell plating measured at right angles to the clearly defined turn of bilge the tank boundary line
bottom shell plating is not less than: shall run parallel to the line of the midship flat bottom.
For suction wells in cargo tanks, the provisions of
B 3.2.4 apply accordingly.
h = [m] or
15

new B.2.3.1
= 2, 0 m, whichever is lesser
3.3.2 Limitation of cargo tank capacity
h min = 1, 0 m
The capacity of each cargo tank of ships less than
In the turn of bilge area or at locations without a 5000 tdw is not to exceed 700 m³, unless wing tanks
clearly defined turn of bilge, where the distances h and or spaces are arranged in accordance with 3.2.2 com-
w are different, the distance w shall have preference at plying with:
levels exceeding 1,5 h above the baseline. For details
2, 4 ⋅ tdw
see MARPOL 73/78, Annex I, Reg. 19.3.3. w = 0, 4 + [ m]
20 000

new B.2.2.3 w min = 0, 76 m

3.2.4 Suction wells in cargo tanks
new B.2.3.2

Suction wells in cargo tanks may protrude into the 3.4 Limitation of cargo tank length
double bottom below the boundary line defined by the
distance h provided that such wells are as small as 3.4.1 For oil and product tankers of less than
practicable and the distance between the well bottom 5000 tdw, the length of cargo tanks measured between
and the bottom shell plating is not less than 0,5 h. oil tight bulkheads is not to exceed 10 m or the values
listed in Table 24.1, whichever is greater.

new B.2.2.4
Chapter 1 Section 24 A Oil Tankers I - Part 1
Page 24–4 GL 2012

new B.2.4.1
new B.3.1

4.2 Definitions
Table 24.1 Permissible length of cargo tanks
Unless expressly stated otherwise the following defi-
Number of nitions apply in the context of this Section.
longitudinal
Permissible length
new A.3
bulkheads
within the 4.2.1 Flashpoint
cargo tanks
Flashpoint is the temperature in degrees Celsius [°C]
 bi  at which a product will give off enough flammable
–  + 0,1 Lc , max. 0,2 Lc vapour to be ignited.
2B 

new A.3
 bi 
1  + 0,15  Lc , max. 0,2 Lc 4.2.2 Control stations
4B 
Control stations are those spaces in which ship's radio
Centre tanks: or main navigating equipment or the emergency
source of power is located or where the fire-recording
bi or fire-control equipment is centralized. This does not
0, 2 Lc , if ≥ 0, 2
B include special fire-control equipment which can be
most practically located in the cargo area.
 bi  b
 + 0,1 Lc , if i < 0, 2 and
 2 B  B
new A.3

no centreline longitudinal bulkhead 4.2.3 Cofferdam

2 and more is provided Cofferdam is the isolating space between two adjacent
steel bulkheads or decks. This space may be a void
 bi  b
 + 0,15  Lc , if i < 0,2 and space or a ballast space.
4B  B
The following spaces may also serve as cofferdams:
a centreline longitudinal bulkhead oil fuel tanks as well as cargo pump rooms and pump
is provided rooms not having direct connection to the machinery
space, passage ways and accommodation spaces. The
Wing cargo tanks: 0,2 Lc clear spacing of cofferdam bulkheads is not to be less
than 600 mm.
bi = minimum distance from the ship's side to inner hull
of the tank in question measured inboard at right
new A.3
angles to the centreline at the level corresponding
to the summer load line. 4.2.4 Cargo service spaces
Cargo service spaces are spaces within the cargo area
3.4.2 Where the tank length exceeds 0,1 L and/or used for workshops, lockers and storerooms of more
the tank breadth exceeds 0,6 B calculations have to be than 2 m² in area used for cargo handling equipment.
carried out in accordance with Section 12, C.1. to
examine if the motions of liquids in partially filled
new A.3
tanks will be in resonance with the pitching or heeling
4.2.5 Cargo deck
motions of the vessel.
Cargo deck means an open deck within the cargo area,

new B.2.4.2
– which forms the upper crown of a cargo tank; or
Note – above which cargo tanks, tank hatches, tank
Reference is also made to MARPOL 73/78, Annex I, cleaning hatches, tank gauging openings and in-
Reg. 23 concerning limitation of cargo tank sizes. spection holes as well as pumps, valves and
other appliances and fittings required for loading

new B.2.4.2 Note and discharging are fitted

new A.3
4. Ship arrangement
4.2.6 Cargo pump room
4.1 General
Cargo pump room is a space containing pumps and
The requirements according to 4.3.2 – 4.3.4, 4.3.8 – their accessories for the handling of products covered
4.3.10 and 4.4.1 – 4.4.3 apply to ships of 500 tons by this Section.
gross tonnage and over.

new A.3
I - Part 1 Section 24 A Oil Tankers Chapter 1
GL 2012 Page 24–5

4.2.7 Hold space 4.2.13 Pump room

Hold space is a space enclosed by the ship's structure Pump room is a space, located in the cargo area, con-
in which an independent cargo tank is situated. taining pumps and their accessories for the handling of
ballast and oil fuel.

new A.3

new A.3
4.2.8 Cargo area
4.2.14 Slop tank
Cargo area is that part of the ship that contains cargo Slop tank is a tank for the retention of oil residues and
tanks, slop tanks, cargo pump rooms including pump oily wash water residues according to Reg. 1.15 of
rooms, cofferdams, ballast or void spaces adjacent to Annex I of MARPOL 73/78.
cargo tanks or slop tanks and also deck areas through-
out the entire length and breadth of the part of the ship
new A.3
over the above-mentioned spaces.
4.2.15 Accommodation spaces
Where independent tanks are installed in hold spaces, Accommodation spaces are those spaces used for
cofferdams, ballast or void spaces at the after end of the public spaces, corridors, lavatories, cabins, offices,
aftermost hold space or at the forward end of the for- hospitals, cinemas, games and hobbies rooms, barber
ward most hold space are excluded from the cargo area. shops, pantries containing no cooking appliances and

new A.3 similar spaces. Public spaces are those portions of the
accommodation spaces which are used for halls, din-
4.2.9 Void space ing rooms, lounges and similar permanently enclosed
spaces.
Void space is an enclosed space in the cargo area
external to a cargo tank other than a hold space, ballast
new A.3
space, oil fuel tank, cargo pump room, pump room, or
any space in normal use by personnel. 4.2.16 Service spaces
Service spaces are those spaces used for galleys, pan-

new A.3
tries containing cooking appliances, lockers, mail and
4.2.10 Machinery spaces specie rooms, store-rooms, workshops other than
those forming part of machinery spaces and similar
Machinery spaces are all machinery spaces of Cate- spaces and trunks to such spaces.
gory A and all other spaces containing propelling
machinery, boilers, oil fuel units, steam and internal
new A.3
combustion engines, generators and major electrical
machinery, oil filling stations, refrigerating, stabiliz- 4.3 Location and separation of spaces
ing, ventilation and air conditioning machinery, and 4.3.1 Cargo tanks are to be segregated by means of
similar spaces; and trunks to such spaces. cofferdams from all spaces which are situated outside

new A.3 the cargo area (see also 4.3.5 – 4.3.7).
A cofferdam between the forward cargo tank and the
4.2.11 Machinery spaces of Category A
forepeak may be dispensed with if the access to the
Machinery spaces of Category A are those spaces and forepeak is direct from the open deck, the forepeak air
trunks to such spaces which contain: and sounding pipes are led to the open deck and port-
able means are provided for gas detection and inerting
– internal combustion machinery used for main the forepeak.
propulsion; or

new B.3.2.1
– internal combustion machinery used for pur-
poses other than main propulsion where such 4.3.2 Machinery spaces are to be positioned aft of
machinery has in the aggregate a total power cargo tanks and slop tanks; they are also to be situated
output of not less than 375 kW; or aft of cargo pump-rooms and cofferdams, but not
necessarily aft of the oil fuel tanks. Any machinery
– any oil-fired boiler or oil fuel unit
space is to be isolated from cargo tanks and slop tanks

new A.3 by cofferdams, cargo pump-rooms, oil fuel tanks or
ballast tanks. Pump-rooms containing pumps and their
4.2.12 Oil fuel unit accessories for ballasting those spaces situated adja-
Oil fuel unit is the equipment used for the preparation cent to cargo tanks and slop tanks and pumps for oil
of oil fuel for delivery to an oil-fired boiler, or equip- fuel transfer may be considered as equivalent to a
ment used for the preparation for delivery of heated oil cargo pump-room within the context of this regula-
to an internal combustion engine and includes any oil tion, provided that such pump-rooms have the same
pressure pumps, filters and heaters dealing with oil at safety standard as that required for cargo pump-rooms.
a pressure of more than 1,8 bar (gauge). However, the lower portion of the pump-room may be
recessed into machinery spaces of category A to ac-

new A.3 commodate pumps, provided that the deck head of the
Chapter 1 Section 24 A Oil Tankers I - Part 1
Page 24–6 GL 2012

recess is in general not more than one third of the 4.3.6 Where it is intended to carry products with a
moulded depth above the keel, except that in the case flashpoint (closed cup test) above 60 °C only, the
of ships of not more than 25 000 tdw, where it can be cofferdams according to 4.3.1 – 4.3.5 need not be
demonstrated that for reasons of access and satisfac- arranged (see also 1.7 and 2.6).
tory piping arrangements this is impracticable, a re-
cess in excess of such height, but not exceeding one
new :B.3.2.6
half of the moulded depth above the keel may be per- 4.3.7 On special tankers cofferdams may be re-
mitted. quired between cargo tanks and oil fuel tanks on ac-

new B.3.2.2 count of the hazards presented by the special products
intended to be carried.
4.3.3 Accommodation spaces, main cargo control
stations and service spaces (excluding isolated cargo
new B.3.2.7
handling gear lockers) are to be positioned aft of all
cargo tanks, slop tanks and spaces which isolate cargo 4.3.8 Where the fitting of a navigation position
or slop tanks from machinery spaces but not necessar- above the cargo area is shown to be necessary, it is
ily aft of the oil fuel bunker tanks and ballast tanks, allowed for navigation purposes only and it is to be
but are to be arranged in such a way that a single fail- separated from the cargo tanks deck by means of an
ure of a deck or bulkhead will not permit the entry of open space with a height of at least 2 m. The fire pro-
gas or fumes from the cargo tanks or slop tanks into an tection of such a navigation position is in addition to
accommodation space, main cargo control station, be as required for control spaces in Section 22, F.4.
control station, or service space. A recess provided in and other provisions, as applicable, of Section 22.
accordance with 4.3.2 need not be taken into account
new B.3.2.8
when the position of these spaces is being determined.
4.3.9 Means are to be provided to keep deck spills

new B.3.2.3 away from the accommodation and service areas. This
4.3.4 However, where deemed necessary, accom- may be accomplished by provision of a permanent
modation spaces, main cargo control stations, control continuous coaming of a suitable height (approx.
stations and service spaces may be permitted forward 150 mm, however, not less than 50 mm above upper
of the cargo tanks, slop tanks and spaces which isolate edge of sheer strake) extending from side to side.
cargo and slop tanks from machinery spaces but not Special consideration is to be given to the arrange-
necessarily forward of oil fuel bunker tanks or ballast ments associated with stern loading.
tanks. Machinery spaces, other than those of category
new B.3.2.9
A, may be permitted forward of the cargo tanks and
slop tanks provided they are isolated from the cargo Note
tanks and slop tanks by cofferdams, cargo pump-
rooms, oil fuel bunker tanks or ballast tanks and sub- Furthermore the corresponding rules of the respective
ject to an equivalent standard of safety and appropriate national administrations are to be observed.
availability of fire-extinguishing arrangements being
new B.3.2.9 Note
provided. Accommodation spaces, main cargo control
spaces, control stations and service spaces are to be 4.3.10 For exterior boundaries of superstructures,
arranged in such a way that a single failure of a deck see Section 22, F.2.1.
or bulkhead will not permit the entry of gas or fumes
from the cargo tanks or slop tanks into such spaces. In
new B.3.2.10
addition, where deemed necessary for the safety or
navigation of the ship, machinery spaces containing 4.4 Arrangement of doors, windows and air
internal combustion machinery not being main propul- inlets
sion machinery having an output greater than 375 kW 4.4.1 Entrances, air inlets and outlets and openings to
may be permitted to be located forward of the cargo accommodation spaces, service spaces, control stations
area provided the arrangements are in accordance with and machinery spaces shall not face the cargo area. They
the provisions of this paragraph. shall be located on the transverse bulkhead not facing

new B.3.2.4 the cargo area and/or on the outboard side of the super-
structure or deckhouse at a distance of at least 4 % of
4.3.5 Where a corner-to-corner situation occurs the length of the ship Lc but not less than 3 m from the
between a safe space and a cargo tank, the safe space end of the superstructure or deckhouse facing the cargo
is to be protected by a cofferdam. Subject to agree- area. This distance, however, need not exceed 5 m.
ment by the owners this protection may be formed by
an angle bar or a diagonal plate across the corner.
new B.3.3.1
Such cofferdam if accessible is to be capable of being
ventilated and if not accessible is to be filled with a 4.4.2 Access doors may be permitted in boundary
suitable compound. bulkheads facing the cargo area or within the limits
specified in 4.4.1, to main cargo control stations and

new B.3.2.5 to such service spaces as provision rooms, store rooms
and lockers, provided they do not give access directly
I - Part 1 Section 24 A Oil Tankers Chapter 1
GL 2012 Page 24–7

or indirectly, to any other space containing or pro- 5.4 The provisions of 4.3.9, 4.4.1, 4.4.2 and 4.4.3
vided for accommodation, control stations or service apply to the exterior boundaries of superstructures and
spaces such as galleys, pantries or workshops, or simi- deckhouses enclosing accommodation spaces, main
lar spaces containing sources of vapour ignition. The cargo control stations, control stations, service spaces
boundaries of such space shall be insulated to "A-60" and machinery spaces which face the cargo shore
standard, with the exception of the boundary facing connection, the overhanging decks which support such
the cargo area. Bolted plates for removal of machinery spaces, and the outboard sides of the superstructures
may be fitted within the limits specified in 4.4.1. and deckhouses for the specified distances from the
Wheelhouse doors and wheelhouse windows may be boundaries which face the cargo shore connection.
located within the limits specified in 4.4.1 so long as

new B.4.4
they are designed to ensure that the wheelhouse can be
made rapidly and efficiently gas and vapour tight. 5.5 Tankers equipped for single point offshore

new B.3.3.2 mooring and bow loading arrangements should in
addition to the provision of 5.1 to 5.4 comply with the
4.4.3 Windows and side scuttles facing the cargo following:
area and on the sides of the superstructures and deck-
houses within the limits specified in 4.4.1 shall be of – Where a forward bridge control position is ar-
the fixed (non-opening) type. Such windows and side ranged on the fore deck, provisions are to be
scuttles, except wheelhouse windows, shall be con- made for emergency escape from the bridge
structed to "A-60" class standard and shall be of an control position in the event of fire.
approved type. – An emergency quick release system is to be

new B.3.3.3 provided for cargo hose and mooring chain.
Such systems are not to be installed within the
4.5 Pipe tunnels in double bottoms fore ship.

Where pipe tunnels are arranged in double bottoms the – The mooring system is to be provided with a
following is to be observed: tension meter continuously indicating the ten-
sion in the mooring system during the bow load-
– Pipe tunnels are not permitted to have direct ing operation. This requirement may be waived
connections with machinery spaces neither if the tanker has in operation equivalent equip-
through openings nor through piping. ment, e.g. a dynamic positioning system ensur-
– At least two access openings with watertight ing that the permissible tension in the mooring
covers are to be fitted and are to be spaced at system is not exceeded.
maximum practicable distance. One of these – An operation manual describing emergency
openings may lead into the cargo pump room. procedures such as activation of the emergency
Other openings shall lead to the open deck. quick release system and precautions in case of
– Adequate mechanical ventilation is to be pro- high tension in the mooring system, should be
vided for a pipe tunnel for the purpose of vent- provided on board.
ing prior to entry (see also the GL Rules for Ma-
new B.4.5
chinery Installations (I-1-2), Section 15).
5.6 For piping details and for the fire extinguish-

new B.3.4
ing systems the provisions of the GL Rules for Ma-
chinery Installations (I-1-2), Section 15 apply.
5. Bow or stern loading and unloading ar-
rangements
new B.4.6

5.1 Subject to special approval, cargo piping may 6. Superstructures

be fitted to permit bow or stern loading or unloading.
Portable piping is not permitted. 6.1 According to Regulation 39 of ICLL, a mini-

new B.4.1 mum bow height above the waterline is required at the
forward perpendicular.
5.2 Outside the cargo area bow and stern loading
new C.1
and unloading lines are to be arranged on the open
deck. 6.2 Machinery and boiler casings are to be pro-

new B.4.2 tected by an enclosed poop or bridge of not less than
standard height, or by a deckhouse of not less than
5.3 When stern loading and unloading arrange- standard height and equivalent strength. Details shall
ments are in use, openings and air inlets to enclosed be taken from ICLL, Reg. 26.
spaces within a distance of 10 metres from the cargo The end bulkheads are to have scantlings as required
shore connection are to be kept closed. in Section 16.

new B.4.3
Chapter 1 Section 24 A Oil Tankers I - Part 1
Page 24–8 GL 2012

new C.2 7.2 Type "A" ships with bulwarks shall have
open rails fitted for at least half the length of the
6.3 Openings in superstructure end bulkheads are weather deck or other equivalent freeing arrange-
to be provided with weather tight closing appliances. ments. A freeing port area, in the lower part of the
Their sills are not to be less than 380 mm in height. bulwarks, of 33 % of the total area of the bulwarks, is
Reference is made to the respective requirements of an acceptable equivalent freeing arrangement. The
the ICLL. upper edge of the sheer strake shall be kept as low as
practicable.

new C.3
Where superstructures are connected by trunks, open
rails shall be fitted for the whole length of the exposed
7. Gangways, bulwarks parts of the freeboard deck.
7.1 Either a permanent and continuous walkway
new D.1.2
on the freeboard deck or a corresponding gangway of
substantial strength (e.g. at the level of the superstruc- 8. Ventilators
ture deck) shall be provided between the deckhouse
and the forecastle on or near the centre line of the ship. 8.1 Ventilators for spaces under the freeboard
For these the following conditions shall be observed: deck are to be of strong construction, or to be effi-
ciently protected by superstructures or other equiva-
– The clear width shall be between 1m and 1,5 m. lent means.
For ships of less than 100 m in length the width
may be reduced to 0,6 m.
new D.2.1
– If the length of the deck to be traversed exceeds 8.2 Pump rooms, cofferdams and other rooms
70 m shelters of sufficient strength at intervals adjacent to cargo tanks are to be fitted with ventilation
not exceeding 45 m shall be provided. Each arrangements, as per GL Rules for Machinery Installa-
shelter shall be capable of accommodating at tions (I-1-2), Section 15.
least one person and be so constructed as to af-
ford weather protection on the forward, port and
new D.2.2
starboard side.
8.3 The dangerous zones as per GL Rules for
– They shall be fitted with guard rails and a foot- Electrical Installations (I-1-3), Section 14, B. are to be
stop on either side. The guard rails shall have a observed.
height of not less than 1 m and shall be fitted
with two courses and with a handrail. The in-
new D.2.3
termediate opening to the lowest course shall
not exceed 230 mm and between the other 9. Anchor equipment
courses it shall not exceed 380 mm. Stanchions
shall be fitted at intervals of not more than 9.1 The anchor windlass and the chain locker are
1,5 m. Every third stanchion shall be fitted with considered a source of ignition. Unless located at least
a support. 2,4 m above the cargo deck the windlass and the open-
ings of chain pipes leading into the chain locker are to
– At all the working areas, but at least every 40 m, be fitted at a distance of not less than 3 m from the
there shall be access to the deck. cargo tank boundaries, if liquids having a flashpoint
– The construction of the gangway shall be of (closed cup test) not exceeding 60 °C are intended to
suitable strength, shall be fire resistant and the be carried.
surface shall be of non-slip material.

new D.3.1
Ships with hatches may be fitted with two walkways
as specified above on the port and starboard side of 9.2 For distances from cargo tank vent outlets
the hatch, located as close as practicable to the ship's etc. the relevant requirements of the GL Rules for Ma-
centre line. chinery Installations (I-1-2), Section 15 are to be ob-
served.
Alternatively a well-lit and sufficiently ventilated
passageway of at least 800 mm width and 2 000 mm
new D.3.2
height can be constructed below the weather deck, as
close as possible to the freeboard deck. 10. Emergency towing arrangements

new D.1.1
10.1 Purpose
Note Under regulation II-1/3-4 of the 1974 SOLAS Con-
vention, as amended in 2000 by Resolution
The respective regulations of the competent national
MSC.99(73), new and existing tankers of 20 000 ton-
authorities are to be observed.
nes deadweight and above shall be fitted with an

new D.1.1 Note emergency towing arrangement in the bow and stern
areas of the upper deck.
I - Part 1 Section 24 A Oil Tankers Chapter 1
GL 2012 Page 24–9

new D.4.1 pollution. The arrangements shall at all times be capa-

ble of rapid deployment in the absence of main power
10.2 Requirements for the arrangements and on the ship to be towed and of easy connection to the
components towing vessel. Fig. 24.1 shows typical arrangements
which may be used as reference.
10.2.1 General

new D.4.2.1
The emergency towing arrangements shall be so de-
signed as to facilitate salvage and emergency towing
operations on tankers primarily to reduceAft
the risk of Fore
Towed vessel

Strongpoints
Chafing gear
Fairleads

Towing pennant

Towing connection

Pick-up gear

Marker buoy

Fig. 24.1 Typical emergency towing arrangements

10.2.2 Documents to be submitted 10.2.4 Length of towing pennant

The following documents have to be submitted for The towing pennant shall have a length of at least
approval: twice the lightest seagoing ballast freeboard at the
– general layout of the bow and stern emergency fairlead plus 50 m.
towing arrangements
new D.4.2.4
– drawings of the bow and stern strong points and
fairleads including material specifications and 10.2.5 Location of strongpoint and fairlead
strength calculations
The strong points and fairleads shall each be located in
– drawings of the local ship structures supporting the bow and stern areas at the centerline.
the loads from the forces applied to the emer-
gency towing equipment
new D.4.2.5

– operation manual for the bow and stern emer- 10.2.6 Strongpoint
gency towing equipment The inboard end fastening shall be a chain cable stop-

new D.4.2.2 per or towing bracket or other fitting of equivalent
strength. The strongpoint can be designed integral
10.2.3 Strength of the towing components with the fairlead. The scantlings of the strong points
and the supporting structures are to be determined on
Towing components shall have a safe working load
the basis of the ultimate strength of the towing pen-
(SWL) of at least 1 000 kN for tankers of 20 000 ton-
nant.
nes deadweight and over but less than 50 000 tonnes
deadweight, and at least 2 000 kN for tankers of
new D.4.2.6
50 000 tonnes deadweight and over. The SWL is de-
fined as one half of the minimum breaking load of the 10.2.7 Fairleads
towing pennant. The strength shall be sufficient for all The bending ratio (towing pennant bearing surface
relevant angles of towline, i.e. up to 90° from the diameter to towing pennant diameter) of the fairlead
ship's centerline to port and starboard and 30° vertical shall not be less than 7 to 1. Otherwise a chafing gear
downwards. (stud link chain) is required.

new D.4.2.3
Chapter 1 Section 24 A Oil Tankers I - Part 1
Page 24–10 GL 2012

new D.4.2.7 10.3.3 The forward emergency towing arrangement

shall be capable of being deployed in harbour condi-
10.2.8 Chafing gear tions in not more than one hour.
10.2.8.1 The chafing gear shall be long enough to
new D.4.3.3
ensure that the towing pennant remains outside the
fairlead during the towing operation. A chain extend- 10.3.4 All emergency towing arrangements shall be
ing from the strongpoint to a point at least 3 m beyond clearly marked to facilitate safe and effective use even
the fairlead shall meet this criterion. in darkness and poor visibility.

new D.4.2.8.1
new D.4.3.4

10.2.8.2 One end of the chafing chain shall be suitable 11. Cathodic protection
for connection to the strongpoint. The other end shall
be fitted with a standard pear-shaped open link allow- 11.1 Impressed current systems and magnesium or
ing connection to a standard bow shackle. magnesium alloy anodes are not permitted in oil cargo
tanks. There is no restriction on the positioning of zinc

new D.4.2.8.2
anodes.
10.2.9 Towing connection
new E.2.1
The towing pennant shall have a hard eye-formed 11.2 When anodes are fitted in tanks they are to be
termination allowing connection to a standard bow securely attached to the structure. Drawings showing
shackle. their location and the attachment are to be submitted.

new D.4.2.9
new E.2.2
10.2.10 Testing 11.3 Aluminium anodes are only permitted in
The breaking load of the towing pennant shall be cargo tanks of tankers in locations where the potential
demonstrated. All components such as chafing gear, energy does not exceed 275 Nm. The height of the
shackles and standard pear-shaped open links shall be anode is to be measured from the bottom of the tank to
tested in the presence of a GL surveyor under a proof the centre of the anode, and its weight is to be taken as
load of 1 420 kN or 2 640 kN respectively, corre- the weight of the anode as fitted, including the fitting
sponding to a SWL of 1 000 kN or 2 000 kN (see devices and inserts. However, where aluminium an-
10.2.3). odes are located on or closely above horizontal sur-
faces such as bulkhead girders and stringers not less
The strong points of the emergency towing arrange- than 1 metre wide and fitted with an upstanding flange
ments shall be prototype tested before the installation or face flat projecting not less than 75 mm above the
on board under a proof load of 2 × SWL. horizontal surface, the height of the anode may be
measured from this surface. Aluminium anodes are
On board, the rapid deployment in accordance with
not to be located under tank hatches or Butterworth
10.3 shall be demonstrated.
openings (in order to avoid any metal parts falling on

new D.4.2.10 the fitted anodes) unless protected by the adjacent
structure.
10.3 Ready availability of towing arrangements
new E.2.3
Emergency towing arrangements shall comply with
the following criteria: 11.4 The anodes should have cores of hull struc-
tural steel or other weldable steel and these should be

new D.4.3 sufficiently rigid to avoid resonance in the anode sup-
port and be designed so that they retain the anode even
10.3.1 The aft emergency towing arrangement shall
when it is wasted.
be pre-rigged and be capable of being deployed in a
controlled manner in harbour conditions in not more The steel inserts are to be attached to the structure by
than 15 minutes. means of a continuous weld of adequate section. Al-
ternatively, they may be attached to separate supports

new D.4.3.1
by bolting, provided a minimum of two bolts with
10.3.2 The pick-up gear for the aft towing pennant lock-nuts are used. When anode inserts or supports are
shall be designed at least for manual operation by one welded to the structure, they should be arranged so
person taking into account the absence of power and that the welds are clear of stress risers.
the potential for adverse environmental conditions that The supports at each end of an anode should not be
may prevail during such emergency towing opera- attached to separate items which are likely to move
tions. The pick-up gear shall be protected against the independently.
weather and other adverse conditions that may prevail.
However, approved mechanical means of clamping

new D.4.3.2 will be accepted.
I - Part 1 Section 24 A Oil Tankers Chapter 1
GL 2012 Page 24–11

new E.2.4
new F.3 Note

12. Aluminium paints

0
Aluminium paints are not to be applied in cargo tanks,

30
on tank decks in way of cargo tanks, in pump rooms,

800
cofferdams or any other spaces where inflammable
cargo gas may accumulate.

30
0

new E.3

13. Access to spaces in the cargo area 600

13.1 Access to cofferdams, ballast tanks, cargo
tanks and other spaces in the cargo area is to be direct 13.4 For oil tankers of less than 5 000 tonnes
from the open deck and such as to ensure their com- deadweight smaller dimensions may be approved by
plete inspection. Access to double bottom spaces may the Administration in special circumstances, if the
be through a cargo pump room, pump room, deep ability to transverse such openings or to remove an
cofferdam, pipe tunnel or similar compartments, sub- injured person can be proved to the satisfaction of the
ject to consideration of ventilation aspects. Administration.

new F.1
new F.4

13.5 With regard to accessibility for survey pur-

Note
poses of cargo and ballast tanks see also Section 21,
Access to double bottom tanks located under cargo N. and the GL Rules for Classification and Surveys (I-
tanks through manholes in the inner bottom may be 0), Section 4, A.
permitted in special cases where non-dangerous liquid
substances only are carried in the cargo tanks and
new F.5
subject to approval by the Administration, however,
13.6 Any tank openings, e.g. tank cleaning open-
not to oil fuel double bottom tanks.
ings, ullage plugs and sighting ports are not to be

new F.1 Note arranged in enclosed spaces.

13.2 For access through horizontal openings,
new F.6

hatches or manholes, the dimensions are to be suffi-
13.7 Ullage plugs and sighting ports are to be
cient to allow a person wearing a self-contained, air-
fitted as high as possible, for instance in the hatchway
breathing apparatus and protective equipment to as-
covers. The openings are to be of the self-closing type
cend or descend any ladder without obstruction and
capable of being closed oil tight upon completion of
also to provide a clear opening to facilitate the hoist-
the sounding operation. Covers may be of steel,
ing of an injured person from the bottom of the space.
bronze or brass, however, aluminium is not an accept-
The minimum clear opening is to be not less than
able material. Where the covers are made of glass
600 mm by 600 mm.
fibre reinforced plastic or other synthetic materials, E.

new F.2 is to be observed.

13.3 For access through vertical openings, or
new F.7

manholes providing passage through the length and
13.8 Where deck openings for scaffolding wire
breadth of the space, the minimum clear opening is to
connections are provided, the following requirements
be not less than 600 mm by 800 mm at a height of not
are to be observed:
more than 600 mm from the bottom shell plating un-
less gratings or other footholds are provided. – The number and position of holes in the deck
are to be approved.

new F.3
– The closing of holes may be by screwed plugs
Note of steel, bronze, brass or synthetic material,
For the purpose of 13.2 and 13.3 the following ap- however, not of aluminium. The material used
plies: shall be suitable for all liquids intended to be
carried.
1. The term “minimum clear opening of not less
than 600 mm × 600 mm“ means that such open- – Metal plugs are to have fine screw threads.
ings may have corner radii up to 100 mm maxi- Smooth transitions of the threads are to be main-
mum. tained at the upper and lower surface of the deck
plating.
2. The term "minimum clear opening of not less
than 600 mm × 800 mm" includes also an open- – Where synthetic material is used, the plugs are
ing of the following size: to be certified to be capable of maintaining an
Chapter 1 Section 24 B Oil Tankers I - Part 1
Page 24–12 GL 2012

effective gastight seal up to the end of the first 15. Corrosion protection
20 minutes of the standard fire test as defined in
The requirements of Section 35 apply, as far as applicable.
Regulation II-2/3.2, SOLAS 74, the test being
applied to the upper side which would in prac-
new E.1
tice be exposed to the flames.
– The number of spare plugs to be kept on board
is to cover at least 10 per cent of the total num- B. Strength of Girders and Transverses in the
ber of holes. Cargo Tank Area

new F.8 1. General

1.1 Girders and transverses may be pre-designed
14. Minimum thickness
according to Section 12, B.3. Subsequently a stress
14.1 In cargo and ballast tanks within the cargo analysis according to 2. is to be carried out.
area the thickness of longitudinal strength members,
new H.1.1
primary girders, bulkheads and associated stiffeners is
not to be less than the following minimum value: All structural elements exposed to compressive stresses
are to be subjected to a buckling analysis according to
t min = 6,5 + 0, 02 L [mm] Section 3, F.
where L need not be taken greater than 250 m. For
new Section 3, D.1
secondary structures such as local stiffeners tmin need
not be taken greater than 9,0 mm. 1.2 Brackets fitted in the corners of transverses
and tripping brackets fitted on longitudinals are to

new G.1 have smooth transitions at their toes.
14.2 For pump rooms, cofferdams and void spaces
new H.1.2
within the cargo area as well as for fore peak tanks the
requirements for ballast tanks according to Section 12, 1.3 Well rounded drain holes for oil and air holes
A.7. apply, tmin need not exceed 11,0 mm. are to be provided, they are not to be larger than re-
quired for facilitating efficient drainage and for vent-
For aft peak tanks the requirements of Section 12, ing of vapours. No such holes and no welding scallops
A.7.3 apply. shall be placed near the constraint points of stiffeners

new G.1 and girders and near the toes of brackets.

new H.1.3
14.3 In way of cargo tanks the thickness of side
shell is not to be taken less than: 1.4 Transverses are to be effectively supported to
resist loads acting vertically on their webs.
t min = L ⋅ k [ mm]

new H.1.4
k = material factor 2. Stress analysis

new G.2
A three-dimensional stress analysis is to be carried out
14.4 If the berthing zone is stiffened longitudinally for the primary structural numbers in way of the cargo
and the transverse web frame spacing exceeds circa tank area by applying the FE calculation method. The
3,3 m the side shell plating in way of the berthing analysis is to be based on the loading conditions ac-
zone is to be increased by 10 ⋅ a [%]. The berthing cording to Fig. 24.2 and 24.3 for double hull oil tank-
zone extends from 0,3 m below the ballast waterline to ers with one or two longitudinal oil-tight bulkheads.
0,3 m above the load waterline. In ship's longitudinal Tankers with deviating cargo tank arrangements and
direction it is the area of the side shell which breadth loading conditions will be separately considered. Con-
sideration of additional load cases may be required if
is larger than 0,95 ⋅ B.
deemed necessary by GL.

new G.3

new H.2
I - Part 1 Section 24 B Oil Tankers Chapter 1
GL 2012 Page 24–13

2/3 T
Tmin

if ballast tank
2/3 T

0.9 T

Fig. 24.2 Loading conditions for tankers with one centreline longitudinal bulkhead
2/3 T

2/3 T

2/3 T

Tmin

if ballast tank

Draught
according
0.9 T T T to loading
condition

Fig. 24.3 Loading conditions for tankers with two longitudinal bulkheads

2.1 Structural modelling distribution according to inner and outer pressures and
the global load distribution according to the section forces
obtained from the longitudinal strength calculation.
The longitudinal extent of the FE model is determined
by the geometry of the structure as well as the local load
Chapter 1 Section 24 C Oil Tankers I - Part 1
Page 24–14 GL 2012

Regarding assessment of fatigue strength, GL reserve Table 20.1 of Section 20 whereas loading due to dif-
the right to require examination of structural details by ferent draught, i.e. ship in ballast and ship fully laden
means of local FE models. respectively may be considered according to service
life, see Section 20, B.2.

new H.2.1

new H.2.4
2.2 Loads
Local static and dynamic loads are to be determined 2.5 Cross ties
according to Section 4; global static and dynamic The cross sectional area of the cross ties exposed to
loads according to Section 5. Also the heeling condi- compressive loads is not to be less than:
tion determined by the angle ϕ is to be considered.
P
The internal pressure in the cargo tanks is to be deter- Ak = [cm 2 ] for λ ≤ 100
mined in accordance with the formula for p1 as per 9,5 − 4,5 ⋅ 10−4 ⋅ λ 2
Section 4, D.1. P ⋅ λ2
= [cm 2 ] for λ > 100

new H.2.2 5 ⋅ 10 4

2.3 Permissible stresses λ = ℓ/i = degree of slenderness

2.3.1 Transverse members
ℓ = unsupported span [cm]
Under the given load assumptions the following stress
values are not to be exceeded in the transverses and in i = radius of gyration = I Ak [cm]
the bulkhead girders:
I = smallest moment of inertia [cm4]
bending and axial stresses:
For the first approximation:
150
σx = [N / mm 2 ] P = A · p [kN]
k
A = area supported by one cross tie [m2]
shear stress:
p = load p1 or pd [kN/m2] as per Section 4, D.
100
τ = [N / mm 2 ] Finally the sectional area Ak is to be checked for the
k
load P resulting from the transverse strength calcula-
equivalent stress: tion.

180
new H.2.5

σv = σ2x + 3τ2 = [N / mm 2 ]
k
σx = stress in longitudinal direction of the girder
C. Oiltight Longitudinal and Transverse
k = material factor according Section 2, B.2. Bulkheads
The stress values as per Section 12, B.3.2 are not to be
exceeded when the load p2 as per Section 4, D.1. is 1. Scantlings
applied.
1.1 The scantlings of bulkheads are to be deter-

new H.2.3.1 mined according to Section 12. The thicknesses are
not to be less than the minimum thickness as per A.14.
2.3.2 Longitudinal members For stress and buckling analysis the requirements of
In the longitudinal girders at deck and bottom, the B.1.1 apply.
combined stress resulting from local bending of the
new I.1.1
girder and longitudinal hull girder bending of the ship's
hull under sea load is not to exceed 230/k [N/mm2]. 1.2 The top and bottom strakes of the longitudi-

new 2.3.2 nal bulkheads are to have a width of not less than
0,1 H, and their thickness is not to be less than:
2.4 Fatigue strength – top strake of plating:
A fatigue strength analysis according to Section 20 is tmin = 0,75 × deck thickness
to be carried out. Analogously it shall be based on
I - Part 1 Section 24 E Oil Tankers Chapter 1
GL 2012 Page 24–15

– bottom strake of plating: support the forces induced by the side shell, the longi-
tmin = 0,75 × bottom thickness tudinal bulkheads and the longitudinal girders. The
shear stress is not to exceed 100/k [N/mm²].

new I.1.2

new J.2.1
1.3 The section modulus of horizontal stiffeners
of longitudinal bulkheads is to be determined as for Beyond that, the buckling strength of plate panels is to
longitudinals according to Section 9, B., however, it is be examined.
not to be less than W2 according to Section 12, B.3.
new Section 3, D.1

new I.1.3
The plate thickness is not to be less than the minimum
1.4 The stiffeners are to be continuous in way of thickness according to A.14.
the girders. They are to be attached to the webs of the
new J.2.1
girders in such a way that the support force can be
transmitted observing τzul = 100/k [N/mm2]. 2.2 The stiffeners and girders are to be deter-

new I.1.4 mined as required for an oil tight bulkhead. The pres-
sure pd but disregarding pv according to Section 4,
2. Cofferdam bulkheads D.2. is to be taken for p.
Cofferdam bulkheads forming boundaries of cargo
new J.2.2
tanks are to have the same strength as cargo tank bulk-
heads. Where they form boundaries of ballast tanks or
tanks for consumables the requirements of Section 12
are to be complied with. Where they form boundaries E. Hatches
of pump-room or machinery spaces the scantlings for
watertight bulkheads as required by Section 11 are 1. Tank hatches
sufficient.

new I.2 1.1 Oil tight tank hatches are to be kept to the
minimum number and size necessary for access and
venting.

new K.1.1
D. Wash Bulkheads
1.2 Openings in decks are to be elliptical and
1. General with their major axis in the longitudinal direction,
wherever this is practicable. Deck longitudinals in
1.1 The total area of perforation in wash bulk- way of hatches should be continuous within 0,4 L
heads is to be approximately 5 to 10 per cent of the amidships. Where this is not practicable, compensa-
bulkhead area. tion is to be provided for lost cross sectional area.

new J.1.1
new K.1.2

1.2 The scantlings of the top and bottom strakes 1.3 Coaming plates are to have a minimum thick-
of plating of a perforated centreline bulkhead are to be ness of 10 mm.
as required by C.1.2. Large openings are to be avoided
new K.1.3
in way of these strakes.
The centreline bulkhead is to be constructed in such a 1.4 Hatch covers are to be of steel with a thick-
way as to serve as shear connection between bottom ness of not less than 12,5 mm. Where their area ex-
and deck. ceeds 1,2 m2, the covers are to be stiffened. The cov-
ers are to close oil tight.

new J.1.2

new K.1.4
2. Scantlings
1.5 Other types of oiltight covers may be ap-
proved if found to be equivalent.
2.1 The plate thickness of the transverse wash
bulkheads is to be determined in such a way as to
new K.1.5
Chapter 1 Section 24 G Oil Tankers I - Part 1
Page 24–16 GL 2012

2. Other access arrangements 3.2 The sides may be framed transversely or

longitudinally in accordance with Section 9.
Hatchways to spaces other than cargo tanks situated
on the strength deck, on a trunk or on the forecastle
new L.3.2
deck, also inside open superstructures, are to be fitted
with weather tight steel covers, the strength of which
is to be in accordance with Section 17, C.

new K.2 G. Ships for the Carriage of Dry Cargo or Oil
in Bulk

1. General

F. Structural Details at the Ship's End 1.1 For ships intended to carry dry cargo or oil in
bulk, the regulations of this Section apply as well as
1. General the relevant regulations for the carriage of the respec-
tive dry cargo. For ships intended to also carry dry
cargo in bulk the regulations of Section 23 apply also.
1.1 The following requirements are based on the
For the Character of Classification see A.2.2.
assumption that the bottom forward of the forward
cofferdam and abaft the aft cofferdam bulkhead is
new M.1.1
framed transversely. Approval may be given for other
systems of construction if these are considered equiva- 1.2 Dry cargo and liquid cargo with a flashpoint
lent. (closed cup test) of 60 °C and below are not to be

new L.1.1 carried simultaneously, excepting cargo oil-contami-
nated water (slop) carried in slop tanks complying
with 3.
1.2 For the fore- and after peak, the requirements
of Section 9, A.5. apply.
new M.1.2

new L.1.2 1.3 Prior to employing the ship for the carriage of
dry cargo the entire cargo area is to be cleaned and gas
2. Fore body freed. Cleaning and repeated gas concentration meas-
urements are to be carried out to ensure that dangerous
2.1 Floor plates are to be fitted at every frame. gas concentrations do not occur within the cargo area
The scantlings are to be determined according to during the dry cargo voyage.
Section 8, A.1.2.3.
new M.1.3

new L.2.1
1.4 In way of cargo holds for oil, hollow spaces
in which explosive gases may accumulate are to be
2.2 Every alternate bottom longitudinal is to be
avoided as far as possible.
continued forward as far as practicable by an intercos-
tal side girder of same thickness and at least half the
new M.1.4
depth of the plate floors. The width of their flange is
not to be less than 75 mm. 1.5 Openings which may be used for cargo op-

new L.2.2 erations when bulk dry cargo is carried are not permit-
ted in bulkheads and decks separating oil cargo spaces
from other spaces not designed and equipped for the
2.3 The sides may be framed transversely or carriage of oil cargoes unless equivalent approved
longitudinally in accordance with Section 9. means are provided to ensure segregation and integ-

new L.2.3 rity.

new M.1.5
3. Aft body
2. Reinforcements
3.1 Between the aft cofferdam bulkhead and the
after peak bulkhead the bottom structure is to comply 2.1 In cargo holds for dry cargo in bulk or oil the
with Section 8. following reinforcements are to be carried out.

new L.3.1
new M.2.1
I - Part 1 Section 24 G Oil Tankers Chapter 1
GL 2012 Page 24–17

new M.2.4.2
2.2 Framing
2.4.3 The scantlings of the hatchway coamings are
2.2.1 The scantlings of frames in the oil cargo to be checked for the load according to Section 17,
spaces are to be determined according to Section 9, B.1.1.4.
A.2.2.

new M.2.4.3
Tripping brackets according to Section 9, A.5.5 are to
be fitted at suitable intervals. 2.4.4 The form and size of hatchway covers and
the sealing system shall be adapted to each other in

new M.2.2.1 order to avoid leakages caused by possible elastic
deformations of the hatchways.
2.2.2 In cargo holds which may be partly filled
frames may be required to be strengthened, depending
new M.2.4.4
on the filling ratio.

new M.2.2.2 3. Slop tanks

2.3 Cargo hold bulkheads 3.1 The slop tanks are to be surrounded by cof-
ferdams except where the boundaries of the slop tanks
2.3.1 The scantlings of cargo hold bulkheads are to where slop may be carried on dry cargo voyages are
be determined according to Section 23, B.8. and ac- the hull, main cargo deck, cargo pump room bulkhead
cording to the requirements for oil tankers as per C. or oil fuel tank. These cofferdams are not to be open
to a double bottom, pipe tunnel, pump room or other

new M.2.3.1
enclosed space. Means are to be provided for filling
the cofferdams with water and for draining them.
2.3.2 In cargo holds which may be partly filled the
Where the boundary of a slop tank is the cargo pump
bulkheads may be required to be strengthened, de-
room bulkhead the pump room is not to be open to the
pending on the filling ratio.
double bottom, pipe tunnel or other enclosed space,

new M.2.3.2 however, openings provided with gastight bolted cov-
ers may be permitted.
2.4 Hatchways

new M.3.1
2.4.1 The scantlings of the hatch covers are to be
determined according to Section 17. 3.2 Hatches and tank cleaning openings to slop
tanks are only permitted on the open deck and are to

new M.2.4.1 be fitted with closing arrangements. Except where
they consist of bolted plates with bolts at watertight
2.4.2 Where cargo holds are intended to be partly spacing, these closing arrangements are to be provided
filled the hatchway covers may be required to be with locking arrangements which shall be under the
strengthened depending on the filling ratio and the control of the responsible ship's officer.
location in the ship.

new M.3.2
Chapter 1 Section 24 H Oil Tankers I - Part 1
Page 24–18 GL 2012

H. Product List 1

List of Oils *

Asphalt solutions Gasoline blending stocks

Blending stocks Alkylates - fuel
Roofers flux Reformates
Straight run residue Polymer - fuel

Oils Gasolines
Clarified Casinghead (natural)
Crude oil Automotive
Mixtures containing crude oil Aviation
Diesel oil Straight run
Fuel oil no. 4 Fuel oil no. 1 (kerosene)
Fuel oil no. 5 Fuel oil no. 1-D
Fuel oil no. 6 Fuel oil no. 2
Residual fuel oil Fuel oil no. 2-D
Road oil
Transformer oil Jet fuels
Aromatic oil (excluding vegetable oil) JP-1 (kerosene)
Lubricating oils and blending stocks JP-3
Mineral oil JP-4
Motor oil JP-5 (kerosene, heavy)
Penetrating oil Turbo fuel
Spindle oil Kerosene
Turbine oil Mineral spirit

Distillates Naphtha
Straight run Solvent
Flashed feed stocks Petroleum
Heartcut distillate oil
__________
Gas oil
* This list of oils shall not necessarily be considered as
Cracked comprehensive.

new N
I - Part 1 Section 24 J Oil Tankers Chapter 1
GL 2012 Page 24–19

J. Product List 2

Explanatory Notes

Product name: The product names are identical with those given in Chapter 18 of the IBC Code.
(column a)

UN number: The number relating to each product shown in the recommendations proposed by the
(column b) (column b) United Nations Committee of Experts on the Transport of Dangerous Goods.
UN numbers, where available, are given for information only.

Category: Z = pollution category assigned under MARPOL 73/78, Annex II

(column c)
I = Product to which a pollution category X, Y, or Z has not been assigned.

Flashpoint: Values in ( ) are "open cup values", all other values are "closed cup values".
(column e) – = non-flammable product

Remarks:
In accordance with Annex II of MARPOL 73/78 an "International Pollution Prevention Certificate for the Carriage
of Noxious Liquid Substances in Bulk" (NLS-Certificate) issued by the Flag Administration is required for the car-
riage in bulk of category Z products.
Columns d and e are for guidance only. The date included therein have been taken from different publications.

new O
Chapter 1 Section 24 J Oil Tankers I - Part 1
Page 24–20 GL 2012

UN- Density Flashpoint

Product name Category
number [kg/m3] [°C]

a b c d e
Acetone 1090 Z 790 -18
Alcoholic beverages, n.o.s. 3065 Z < 1000 > 20
Apple juice I < 1000 –
n-Butyl alcohol 1120 Z 810 29
sec-Butyl alcohol 1120 Z 810 24
Butyl stearate I 860 160
Clay slurry I ≈ 2000 –

Coal slurry I ≈ 2000 –

Diethylene glycol Z 1120 143
Ethyl alcohol 1170 I 790 13
Ethylene carbonate I 1320 143
Glucose solution I 1560 –
Glycerine Z 1260 160
Glycerol monooleate Z 950 224
Hexamethylenetetramine solutions Z ≈ 1200 –
Hexylene glycol Z 920 96
Isopropyl alcohol 1219 Z 790 22
Kaolin slurry I 1800 – 2600 –
Magnesium hydroxide slurry Z ≈ 1530 –

N-Methylglucamine solution (70 % or less) Z 1150 > 95

Molasses I 1450 > 60
Non-noxious liquid, n.o.s. (12) (trade name ..., contains ...)
I
Cat. OS
Noxious liquid, n.o.s. (11) (trade name ..., contains ...) Cat. Z Z
Polyaluminium chloride solution Z 1190 – 1300 –
Potassium formate solutions Z ≈ 1570 > 93
Propylene carbonate Z 1190 135
Propylene glycol Z 1040 99
Sodium acetate solutions Z 1450
Sodium sulphate solutions Z > 60
Tetraethyl silicate monomer/oligomer (20 % in ethanol) Z
Triethylene glycol Z 1130 166
Water I 1000 –
I - Part 1 Section 24 K Oil Tankers Chapter 1
GL 2012 Page 24–21

K. Additional Requirements for Tankers in 1.4 Definitions

Shuttle Service
SPM Single point mooring arrangement of basic
design, fitted with local control for mooring
1. General requirements and instructions to single point moorings complying with 2.1.1
SPM1 Single point mooring arrangement of basic
1.1 General design, fitted with local control for mooring
and cargo loading manifold complying with
1.1.1 Scope 2.1, 2.3.1 to 2.3.4 and 2.4.1.3 to 2.4.1.4
These requirements apply to tankers employed in SPM2 Single point mooring arrangement of ad-
shuttle service between offshore ports and terminals vanced design, fitted with bow control sta-
(single point moorings, SPM), floating storage units tion and provided with automatic and re-
(FSU), submerged turret loading (STL) and regular mote control for cargo transfer and ship ma-
ports and terminals. The requirements herein provide noeuvring complying with 2.1, 2.3 and 2.4.1
minimum safety standards for the intended service and SPM3 Single point mooring arrangement of ad-
shall be applied in addition to A. to J. National regula- vanced design, fitted with bow control station
tions for such operations are to be observed, if any. In automatic and remote control for cargo transfer
respect of layout and arrangement of such systems, the and equipped with a dynamic positioning sys-
applicable guidelines and recommendations issued by tem (DPS) complying with 2.1, 2.3, 2.4 and
the Oil Companies International Marine Forum the GL Rules for Dynamic Positioning Sys-
(OCIMF) have been considered as far as necessary. tems (I-1-15)

new P.1.1.1 STL Submerged turret loading arrangement of
specific design combined with a dynamic
1.1.2 Reference to other Rules and Guidelines positioning system (DPS) complying with
2.2 and the GL Rules for Dynamic Position-
The following GL Rules shall be applied in addition: ing Systems (I-1-15)
– Section 1 to 22
new P.1.4
– Chapter 2 – Machinery Installations 1.5 Documents for approval
– Chapter 3 – Electrical Installations In addition to the documents required for regular Class
(as per 1.1.2 above) the following documentation is to
– Chapter 15 – Dynamic Positioning Systems be submitted for approval as applicable:

new P.1.1.2 Single point mooring arrangement:
– plans showing the mooring arrangement with
1.2 Exemptions position of bow fairleads, bow chain stoppers,
winches and capstans, possible pedestal rollers,
Any kind of new or different design may be accepted and winch storage drum
by GL provided that an equivalent level of safety is
demonstrated. – details of bow fairleads and their attachment to
the bulwark

new P.1.2
– details of attachment to deck and supporting struc-
ture of the bow chain stoppers, winch or capstans,
1.3 Notations affixed to the Character of Clas- possible pedestal rollers, and winch storage drum
sification
– a product certificate for the bow chain stoppers and
The following Notations may be assigned within the bow fairleads, confirming compliance with 2.1.1
scope of these requirements to the general Character
of Classification: – documentation for maximum safe working load
(SWL) from manufacturer (works certificate)
– SPM, SPM1, SPM2 or SPM3 for winches or capstans, confirming compliance
with 2.1.1.8
– STL – documentation for maximum safe working load
SPM installations are grouped into four classes as (SWL) from manufacturer (works certificate)
defined in 1.4 and have to comply with the require- for pedestal roller (if fitted), confirming neces-
ments set out in 2. sary structural strength to withstand the forces to
which it will be exposed when the winch or cap-
For further Notations refer to the GL Rules for Dyna- stan are lifting with maximum capacity
mic Positioning Systems (I-1-15). Bow loading arrangement:

new P.1.3
Chapter 1 Section 24 K Oil Tankers I - Part 1
Page 24–22 GL 2012

– plans showing the bow loading and mooring – arrangement of fairleads, chain stopper, winches
arrangements including drawings of their substructures and
bow control station
– detailed drawings and data sheets of quick re-
lease hose coupling, if fitted
– arrangement and details of fire protection equip-
– cargo and vapour return systems, if fitted ment in the bow area
– ventilation of spaces in the bow area incl. bow chain and associated fittings shall be capable to pass
control room freely.
– electrical systems and location of equipment
new P.2.1.1.2
– hydraulic systems 2.1.1.3 Stoppers are to be fitted as close as possible
– arrangement of forward spaces incl. accesses, air to the deck structure and shall be located 2,7 m to
inlets and openings 3,7 m inboard of the fairleads. Due consideration shall
be given to proper alignment of the stopper between
– plan of hazardous areas the fairlead and pedestal lead or drum of the winch or
– operation manual capstan.

Submerged turret loading:
new P.2.1.1.3

– plans showing the STL room arrangement in- 2.1.1.4 For the structural strength of the supporting
cluding hull constructional details and mating structure underneath the chain stoppers the following
platform permissible stresses are to be observed:
– detailed drawings of loading manifold with
200
cargo piping, couplings and hoses σb = [N / mm 2 ]
k
– plans for hydraulically operated components
with hydraulic systems 120
τ = [N / mm 2 ]
– fire protection arrangement of the STL room k
– ventilation arrangement of the STL room 220
σv = σb2 + 3 τ2 = [N / mm 2 ]
– location and details of all electrical equipment k
– arrangement, foundation, substructure and de-
tails of hoisting winch For strength assessment using FEM the following per-
missible equivalent v. Mises stress is to be observed:

I-0, Section 2, D.2
230
σv = [N / mm 2 ]
2. System requirements k

2.1 Requirements for single point mooring The acting forces are to be twice the SWL, as per
(SPM) Table 24.2.

new P.2.1.1.4
2.1.1 Bow chain stoppers and fairleads
2.1.1.1 One or two bow chain stoppers are to be fit- 2.1.1.5 Upon installation, bow stoppers are to be load
ted, capable to accept a standard 76 mm stud-link chain tested to the equivalent safe working load (SWL). A
(chafing chain, as defined in the OCIMF "Recommen- copy of the installation test certificate shall be avail-
dations for Equipment Employed in the Bow Mooring able for inspection on board the ship.
of Conventional Tankers at Single Point Moorings"). Alternatively, the ship shall hold a copy of the manu-
The number of chain stoppers is to be chosen in ac- facturer's type approval certificate for the bow chain
cordance with Table 24.2. For ships of a size of up to stoppers, confirming that bow chain stoppers are con-
150 000 tdw two bow chain stoppers may be fitted to structed in strict compliance with the SWL given in
ensure full range terminal acceptance. The capacity of Table 24.2. This certificate shall also indicate the yield
bow chain stoppers is to be according to 2.1.1.5. strength of the bow chain stoppers. Loads that induce

new P.2.1.1.1 this yield stress shall not be less than twice the SWL.
Applicable strength of the supporting structures under-
2.1.1.2 The design of the chain stopper shall be of an
neath the chain stoppers shall be documented by ade-
approved type, in accordance with the GL Rules for
quate analyses. GL will issue a declaration confirming
Machinery Installations (I-1-2), Section 14, D. The chaf-
ing chain shall be secured when the chain engaging pawl
or bar is in closed position. When in open position, the
I - Part 1 Section 24 K Oil Tankers Chapter 1
GL 2012 Page 24–23

Table 24.2 Arrangement and capacity for SPM

Vessel size Chafe chain size Number of bow Number SWL

fairleads of
[tdw] [mm] (recommended) bow stoppers [kN]
up to 100 000 76 1 1 2 000
over 100 000
76 1 1 2 500
up to 150 000
over 150 000 76 2 2 3 500
that an evaluation verifying sufficient support strength
has been carried out. A copy of the declaration shall be 2.1.2 Bow loading arrangements
available for inspection on board the ship. Bow chain
stoppers and supporting structures underneath the chain 2.1.2.1 Bow loading cargo piping is to be perma-
stoppers shall be subject to periodic class survey. nently fitted and is to be arranged on the open deck.
Outside the cargo area and in way of the bow area

new P.2.1.1.5 only welded connections, except at the bow loading
connection, are permitted.
2.1.1.6 Bow fairleads shall have minimum dimensi-
ons of 600 × 450 mm and shall be of oval or rounded
new P.2.1.2.1
shape. The design force for the fairleads as well as
2.1.2.2 Within the cargo area the bow piping is to be
permissible design stresses for their supporting struc-
separated from the main cargo system by at least two
tures are to be taken according to 2.1.1.4. The design
valves fitted with an intermediate drain or spool piece.
force shall be considered at angles of 90° to the sides
Means for draining towards the cargo area as well as
and 30° upwards or downwards.
purging arrangements with inert gas shall be provided.

new P.2.1.1.6

new P.2.1.2.2
2.1.1.7 Single fairleads should be arranged at the 2.1.2.3 The bow loading connection shall be equipped
centreline, where two fairleads are fitted they should with a shut-off valve and a blank flange. Instead of the
be arranged 1 to 1,5 m from the centreline on either blank flange a patent hose coupling may be fitted.
side. Two bow fairleads are recommended for ships Spray shields are to be provided at the connection
fitted with two bow chain stoppers.
flange and collecting trays are to be fitted underneath

new P.2.1.1.7 the bow loading connection area.

2.1.1.8 Winches or capstans are to be positioned to
new P.2.1.2.3

enable a pull in direct straight lead with the bow fair- 2.1.2.4 Materials and pipe scantlings shall be in
leads and chain stoppers. Alternatively a pedestal compliance with the GL Rules for Machinery Installa-
roller is to be positioned between stopper and winch or tions (I-1-2), Section 11.
capstan. Winches or capstans are to be capable of
lifting at least 15 tonnes.
new P.2.1.2.4

new P.2.1.1.8 2.1.3 Fire fighting arrangements
2.1.1.9 If a winch storage drum is used to stow the 2.1.3.1 The following foam fire-extinguishing equip-
pick-up rope, it shall be capable to accommodate at ment is to be provided for bow loading arrangement:
least 150 m rope of 80 mm in diameter.
– one or more dedicated foam monitor(s) for pro-

new P.2.1.1.9 tecting the bow loading area complying with the
requirements in the GL Rules for Machinery In-
2.1.1.10 The design force for substructures of pedestal
stallations (I-1-2), Section 12, K.
rollers is to be not less than 1,25 times the force ex-
erted by the winch or capstan when lifting with maxi- – one portable foam branch pipe for protecting the
mum capacity. The permissible design stresses are to cargo line forward of the cargo area
be taken according to 2.1.1.4.

new P.2.1.3.1

new P.2.1.1.10
2.1.3.2 A fixed water spray system is to be provided
2.1.1.11 The SWL according to Table 24.2 is to be covering the areas of chain stoppers and bow loading
marked (by weld bead or equivalent) on the chain connection, having a capacity of:
stoppers and fairleads.

new P.2.1.1.11
Chapter 1 Section 24 K Oil Tankers I - Part 1
Page 24–24 GL 2012

litre or portable. If fixed, the connection to the IG-System

10 inlet shall be provided with a blank flange.
2
m ⋅ min

new P.2.2.5
The system shall be capable of being manually oper-
ated from outside the bow loading area and may be 2.2.6 Electrical equipment shall be of certified safe
connected to the forward part of the fire water main line. type in compliance with the GL Rules for Electrical
Installations (I-1-3), Section 15. Where equipment

new P.2.1.3.2
needs to be installed for submerged use, the protection
class shall be IP 68; otherwise, the installation is to be
2.1.4 Electrical equipment
located well above the deepest waterline. Electric
Electrical equipment in hazardous areas and spaces as lighting of the STL room shall be interlocked with the
well as within a radius of 3 m from the cargo loading ventilation such that lights can only be switched on
connection/manifold or any other vapour outlet shall be when the ventilation is in operation.
of certified safe type, meeting the requirements stated Failure of ventilation shall not cause the lighting to
in the GL Rules for Electrical Installations (I-1-3), extinguish. Emergency lighting shall not be inter-
Section 15. locked.

new P.2.1.4
new P.2.2.6
2.2 Requirements for submerged turret load- 2.2.7 A fixed gas detection system shall be fitted
ing (STL) with sampling points or detector heads located at the
lower portions of the room. At least one sampling
2.2.1 The STL room with mating recess shall be point/detector shall be fitted above the deepest water-
arranged in the fore body, but within the cargo area. line. Visual and audible alarms shall be triggered in
The hull structural design (scantlings of mating recess, the cargo control station and on the navigation bridge
mating ring locking device, brackets etc.) shall take if the concentration of flammable vapours exceeds
into account the design loads caused by the cargo 10 % of the lower explosive limit (LEL).
transfer system with due consideration to environ-
mental and operational loads. The designer has to
new P.2.2.7
provide sufficient information about the design loads.
2.3 Arrangement of forward spaces

new P.2.2.1
2.3.1 General
2.2.2 Access to the STL room is only permitted
from open deck. Hazardous zones, areas and spaces shall be defined on
basis of the GL Rules for Electrical Installations (I-1-

new P.2.2.2 3), Section 15.

2.2.3 A permanent mechanical extraction type
new P.2.3.1

ventilation system providing at least 20 changes of air
2.3.2 Air vent pipes from fore peak tanks are to be
per hour shall be fitted. Inlets and outlets shall be
located as far as practicable away from hazardous
arranged at least 3 m above the cargo tank deck, and
areas.
the horizontal distance to safe spaces shall not be less
than 10 m. Design of fans shall conform to the GL
new P.2.3.2
Rules for Machinery Installations (I-1-2), Section 15.
The air inlet shall be arranged at the top of the STL 2.3.3 Access openings, air inlets and outlets or
room. Exhaust trunks are to be arranged having: other openings to service, machinery and other gas
safe spaces shall not face the bow loading area and
– one opening directly above the lower floor and shall be arranged not less than 10 m away from the
one opening located 2 m above this position bow loading connection. These spaces shall have no
– one opening above the deepest waterline connection to gas dangerous spaces and are to be
equipped with fixed ventilation systems.
The openings are to be equipped with dampers capa-
ble of being remotely operated from outside the space.
new P.2.3.3

new P.2.2.3 2.3.4 Spaces housing the bow loading connection

and piping are to be considered as gas dangerous
2.2.4 A fixed fire extinguishing system in accor- spaces and shall preferably be arranged semi-enclosed.
dance with the GL Rules for Machinery Installations In case of fully enclosed spaces, a fixed extraction
(I-1-2), Section 12, D.1.4 is to be provided. type ventilation providing 20 changes of air per hour
shall be fitted. Design of fans shall be according to GL

new P.2.2.4 Rules for Machinery Installations (I-1-2), Section 15.
2.2.5 A connection for the supply of inert gas (IG)
new P.2.3.4
shall be fitted. The connection may be arranged fixed
I - Part 1 Section 24 K Oil Tankers Chapter 1
GL 2012 Page 24–25

2.3.5 A bow control station for SPM or STL load- vessel. The system shall be capable of the following
ing operations may be arranged. Unless agreed other- functions:
wise and approved, this space shall be designed as gas
safe and is to be fitted with fixed overpressure ventila- – stopping of main cargo pumps or tripping of shore
tion with inlets and outlets arranged in the safe area. transfer facilities if a ship to shore link is provided
The access opening shall be arranged outside the haz- – closing manifold and hose coupling valves
ardous zones. If the access opening is located within
the hazardous zone, an air lock is to be provided. – opening the hose coupling
Emergency escape routes shall be considered during – opening the chain stopper
design. Fire protection standards according to "A–60"
In addition to the automatic functions, individual re-
class shall be applied for bulkheads, decks, doors and
lease of hose coupling and chain stoppers shall be
windows in relation to adjacent spaces and areas.
provided.

new p.2.3.5

new P.2.4.1.3
2.4 Functional requirements for bow and STL 2.4.1.4 Communication
loading systems
Means of communication between ship and offshore
2.4.1 Control systems, communication loading terminal shall be provided, certified as "Safe
for use in gas dangerous atmosphere". Procedures for
2.4.1.1 General emergency communication shall be established.
The bow control station, if fitted, may include the ship
new P.2.4.1.4
manoeuvring controls as well as the SPM/STL moor-
ing and cargo transfer control instrumentation. In case 2.4.2 Operation manual
the ship manoeuvring controls are provided on the
navigation bridge only, a fixed means of communica- The tanker shall have on board an operation manual
tion shall be fitted in both locations. Similar arrange- containing the following information:
ments apply to the bow control station and the cargo
– arrangement drawings of the SPM/STL cargo
control room (CCR), where main cargo loading con-
transfer arrangement, bow/STL loading connec-
trols are provided in the CCR only.
tion, mooring system, fire fighting systems and

new P.2.4.1.1 instrumentation
2.4.1.2 Essential instrumentation and controls in – safety instructions with regard to fire fighting
the bow control station and extinction, emergency release procedures
and escape routes
Ship manoeuvring:
– operational procedures for mooring, connecting/
– main propulsion controls disconnecting loading arrangements and com-
– steering gear, thruster controls munication
– radar, log
new P.2.4.2
Bow mooring:
3. Surveys and tests
– mooring chain traction controls. This require-
ment may be waived if the tanker is fitted and 3.1 Tests of components
operating with a dynamic positioning system.
Couplings/connectors intended for bow or STL loading
– chain stopper controls operations shall be of approved design. Approvals or test
reports issued by recognised institutions may be sub-
– data recorder for mooring and load parameters
mitted for review/acceptance. Materials for steel struc-
Bow/STL loading: ture, piping, electrical equipment and cables shall in
general be in compliance with the current GL Rules as
– manifold connector/coupling indicator applicable, see 1.1.2. Cargo transfer hoses and hoses used
– cargo valves position indicator/controls in hydraulic or other systems shall be type approved.
– cargo tank level and high alarm indicators
new P.3.1
– cargo pumps controls 3.2 Tests after installation

new P.2.4.1.2 All systems and equipment used for SPM, bow loading
and STL shall be function tested at the shipyard prior to
2.4.1.3 Emergency release
commissioning. During the first offshore loading opera-
The bow loading arrangements are to be provided tion, an inspection shall be carried out by a local Survey-
with a system for emergency release operation based or. The inspection shall include all relevant operational
on a logical sequence to ensure safe release of the procedures and verification of the operation manual.
Chapter 1 Section 24 K Oil Tankers I - Part 1
Page 24–26 GL 2012

new P.3.2

3.3 Periodical inspections

To maintain the Class Notations assigned for the SPM

and STL installations, annual/intermediate and re-
newal surveys shall be carried out in conjunction with
regular class surveys. The scope of surveys shall be
based on the principles laid down in the GL Rules for
Classification and Surveys (I-0), Section 4, A.

new P.3.3
I - Part 1 Section 25 B Tugs Chapter 1
GL 2012 Page 25–1

Section 25

Tugs

A. General
– slip device(s) including hydraulic/pneumatic
systems and electric circuits, and/or "weak link"
1. Scope, application for towrope on winch drum

1.1 The following requirements apply to vessels – required bollard pull (design value)
primarily designed for towing and/or pushing opera- – towrope specification
tions or assisting other vessels or floating objects in
manoeuvring. Combination with other purposes is – in special cases, intended tow configuration(s)
possible and will be noted accordingly in the Class – For examination of towing gear with towing
Certificate, see 2.2. winch, the direction of the towrope has to be in-

new A.1 and I-0, Section 2, Table 2.9 dicated on the drawings.

I-0, Section 2, D.2
1.2 Unless specially mentioned in this Section,
the requirements of Sections 1 – 22 apply.
3.2 The reliable function of the towing gear has

new A.1 to be proven during the initial tests on board.

ItS
1.3 Special designs not covered by the following
rules will be considered from case to case.
3.3 If a bollard pull test has to be carried out and
1.4 For instructions regarding towing operations will be certified by GL, it shall correspond to the pro-
in general, see the GL Guidelines for Ocean Towage cedure given in the GL Guidelines for Ocean Towage
(VI-11-1). (VI-11-1). The test results shall be documented and
kept on board together with the certificate of bollard

new A.2.2 pull testing and the classification documents.

new D.6.2.2
2. Classification, notations
3.4 GL material certificates will generally be
2.1 Ships built in accordance with the require-
required for:
ments of this Section will have the Notation TUG
affixed to their Character of Classification – towing hook and attached load transmitting

I-0, Section 2, Table 2.9 elements, including slip device
– towing winch, including frame, drum shaft(s),
2.2 Where towing services are to be combined couplings, brakes and gear(s)
with other duties such as offshore supply or ice break-
ing, corresponding additional class notations may be – towrope(s), including certification of breaking
assigned if the relevant requirements are met. force

I-0, Section 2, C.3.3.7 Material certificates according to DIN 50049-3.1B
may be accepted for standard items, if the manufac-
3. Approval documents, documentation turer is recognised by GL.

new B
3.1 In addition to the documents listed in the
rules mentioned under 1.2 above, the following design
documentation shall be submitted, in triplicate, for
approval and/or information:
B. Hull Structures
– general arrangement of the towing gear includ-
ing winch(es), if provided
1. Scantlings, general
– design drawings and material specifications of
towing hook and accessory towing gear, tow- For the determination of hull structure scantlings the
rope guide and/or of the towing winch including draught T is not to be taken less than 0,85 H.
winch drives, brakes and fastening elements
new C.1
Chapter 1 Section 25 B Tugs I - Part 1
Page 25–2 GL 2012

2. Deck structure sides, fendering may be necessary to reduce indenting

damages of the shell plating.
2.1 On tugs for ocean towage, the deck, particu-
new C.5.1
larly in the forward region, shall be suitably protected
or strengthened against sea impact.
5.2 A continuous and suitable strong fender shall

new C.2.1 be arranged along the upper deck.

new C.5.2
2.2 Depending on the towrope arrangement, the
deck in the aft region may have to be strengthened 5.3 For ice strengthening see 8.
(beams, plate thickness), if considerable chafing
and/or impact is to be expected. See also C.1.5.
6. Engine room casing, superstructures and

new C.2.2 deckhouses

3. Fore body, bow structure 6.1 The plate thickness of the casing walls and
casing tops is not to be less than 5 mm. The thickness
3.1 On tugs for ocean towage, strengthening in of the coamings is not to be less than 6 mm. The
way of the fore body (stringers, tripping brackets etc.) coamings shall extend to the lower edges of the
shall generally conform to the indications given in beams.
Section 9. The stringers shall be effectively connected
new C.6.1
to the collision bulkhead. Depending on the type of
service expected, additional strengthening may be 6.2 The stiffeners of the casing are to be con-
required. nected to the beams of the casing top and are to extend

new C.3.1 to the lower edge of the coamings.

new C.6.2
3.2 For (harbour) tugs frequently engaged in
berthing operations, the bow shall be suitably pro- 6.3 Regarding height of casing and closing ar-
tected by fendering and be structurally strengthened. rangements as well as exits see also F.1.1.

new C.3.2
6.4 The following requirements have to be ob-
served for superstructures and deckhouses of tugs
3.3 The bulwark shall be arranged with an inward
assigned for the restricted services areas RSA (50) and
inclination in order to reduce the probability and fre-
RSA (200) or for unlimited range of service:
quency of damages. Square edges are to be chamfered.
– The plate thickness of the external boundaries of

new C.3.3 superstructures and deckhouses is to be in-
creased by 1 mm above the thickness as required
3.4 The bow structure of pusher tugs for sea in Section 16, C.3.2.
service will be specially considered. For pusher tugs
for inland navigation see the GL Rules for Additional – The section modulus of stiffeners is to be in-
Requirements for Notations (I-2-4), Section 2, E. creased by 50 % above the values as required in
Section 16, C.3.1.

new C.3.4

new C.6.3
4. Stern frame
7. Foundations of towing gear
The cross sectional area of a solid stern frame is to be
20 % greater than required according to Section 13, 7.1 The substructure of the towing hook attach-
C.2.1. For fabricated stern frames, the thickness of the ment and the foundations of the towing winch, and of
propeller post plating is to be increased by 20 % com- any guiding elements such as towing posts or fair-
pared to the requirements of Section 13, C.2.2. The leads, where provided, shall be thoroughly connected
section modulus WZ of the sole piece is to be in- to the ship's structure, considering all possible direc-
creased by 20 % compared to the modulus determined tions of the towrope, see C.3.5.
according to Section 13, C.4.

new C.7.1

new C.4
7.2 The stresses in the foundations and fastening
5. Side structure elements shall not exceed the permissible stresses
shown in Table 25.2, assuming a load equal to the test
load of the towing hook in case of hook arrangements,
5.1 The side structure of areas frequently sub-
and a load of the winch holding capacity in case of
jected to impact loads shall be reinforced by increas-
towing winches, see also C.3.5 and C.5.3.
ing the section modulus of side frames by 20 %. Be-
I - Part 1 Section 25 C Tugs Chapter 1
GL 2012 Page 25–3

new C.7.2 2.2 The test force PL is used for dimensioning as

well as for testing the towing hook and connected
elements. The test force is related to the design force
8. Ice strengthening
as shown in Table 25.1.
8.1 Ice strengthening, where necessary according
new D.2.2
to the intended service, shall be provided according to
the requirements of Section 15.
Table 25.1 Design force T and test force PL
8.2 Tugs with the Notation ICEBREAKER have
to be specially considered. Design force T [kN] Test force PL [kN]

up to 500 2T
from 500 to 1 500 T + 500
C. Towing gear/Towing arrangement
above 1 500 1,33 T

1. General design requirements

2.3 The minimum breaking force of the towrope
1.1 The towing gear shall be arranged in such a is based on the design force, see 4.3.
way as to minimise the danger of capsizing; the tow-
ing hook/working point of the towing force is to be
new D.2.3
placed as low as practicable, see also F.
2.4 The winch holding capacity shall be based on

new D.1.1 the minimum breaking force, see 5.3, the rated winch
force is the hauling capacity of the winch drive when
1.2 With direct-pull (hook-towrope), the towing winding up the towrope, see 6.1.3.3.
hook and its radial gear are to be designed such as to
permit adjusting to any foreseeable towrope direction,
new D.2.4
see 3.5.
2.5 For forces at the towing hook foundation see

new D.1.2 3.5.4

1.3 The attachment point of the towrope shall be
new D.2.5

arranged closely behind the centre of buoyancy.
3. Towing hook and slip device

new D.1.3
3.1 The towing hook shall be fitted with an ade-
1.4 On tugs equipped with a towing winch, the
quate device guaranteeing slipping (i.e., quick release)
arrangement of the equipment shall be such that the
of the towrope in case of an emergency. Slipping shall
towrope is led to the winch drum in a controlled man- be possible from the bridge as well as from at least
ner under all foreseeable conditions (directions of the
one other place in the vicinity of the hook itself, from
towrope). Means shall be provided to spool the tow-
where in both cases the hook can be easily seen.
rope effectively on the drum, depending on the winch
size and towing gear configuration.
new D.3.1

new D.1.4
3.2 The towing hook has to be equipped with a
mechanical, hydraulic or pneumatic slip device. The
1.5 Towrope protection sleeves or other adequate
slip device shall be designed such as to guarantee that
means shall be provided to prevent the directly pulled
unintentional slipping is avoided.
towropes from being damaged by chafing/abrasion.

new D.3.2

new D.1.5
3.3 A mechanical slip device shall be designed
2. Definition of loads such that the required release force under test force PL
does not exceed neither 150 N at the towing hook nor
2.1 The design force T corresponds to the tow- 250 N when activating the device on the bridge. In
rope pull (or the bollard pull, if the towrope pull is not case of a mechanical slip device, the releasing rope
defined) stipulated by the owner. The design force shall be guided adequately over sheaves. If necessary,
may be verified by a bollard pull test, see A.3.3 and slipping should be possible by downward pulling,
the GL Guidelines for Ocean Towage (VI-11-1). using the whole body weight.

new D.2.1
new D.3.3
Chapter 1 Section 25 C Tugs I - Part 1
Page 25–4 GL 2012

3.4 Where a pneumatic or hydraulic slip device is stresses in the towing equipment elements defined
used, a mechanical slip device has to be provided above shall not exceed the values shown in Table
additionally. 25.2.

new D.3.4
new D.3.5.3

3.5 Dimensioning of towing hook and towing 3.5.4 For the towing hook foundation it has to
gear be additionally proven that the permissible stresses
given in Table 25.2 are not exceeded assuming a load
3.5.1 The dimensioning of the towing gear is based equal to the minimum breaking force Fmin of the tow-
on the test force PL, see 2.2. rope.

new D.3.5.1
new D.3.5.4
3.5.2 The towing hook, the towing hook founda-
tion, the corresponding substructures and the slip 4. Towropes
device are to be designed for the following directions
of the towrope: 4.1 Towrope materials shall correspond to the
GL Rules for Equipment (II-1-4). All wire ropes
– For a test force PL up to 500 kN:
should have as far as possible the same lay.
– in the horizontal plane, directions from
abeam over astern to abeam The suitability of fibre ropes as towropes is to be sepa-
rately demonstrated to GL.
– in the vertical plane, from horizontal to 60°
upwards
new D.4.1

– For a test force PL of more than 500 kN: 4.2 The length of the towrope shall be chosen
– in the horizontal plane, as above according to the tow formation (masses of tug and
towed object), the water depth and the nautical condi-
– in the vertical plane, from horizontal to 45° tions. Regulations of flag state authorities have to be
upwards observed. For length of towrope for bollard pull test,

new D.3.5.2 see the GL Guidelines for Ocean Towage (VI-11-1).

new D.4.2
3.5.3 Assuming the test force PL acting in any of
the directions described in 3.5.2, the permissible

Table 25.2 Permissible stresses

Type of stress Permissible stress

Axial and bending tension and axial and bending compression with
σ = 0,83 ⋅ ReH
box type girders and tubes
Axial and bending compression with girders of open cross sections
σ = 0,72 ⋅ ReH
or with girders consisting of several members

Shear τ = 0,48 ⋅ ReH

Equivalent stress σ eq = 0,85 ⋅ ReH

4.3 The required minimum breaking force Fmin of

For T between 200 and 1 000 kN, K may be interpo-
the towrope is to be calculated on the basis of the lated linearly.
design force T and a utility factor K, as follows:

new D.4.3
Fmin = K ⋅ T

4.4 For ocean towages, at least one spare towrope

K = 2,5 for T ≤ 200 kN and with attachments shall be available on board.

= 2,0 for T ≥ 1 000 kN
new D.4.4

I - Part 1 Section 25 C Tugs Chapter 1
GL 2012 Page 25–5

4.5 The required minimum breaking force Fmin of 5.2.3 The diameter of the winch drum is to be not
the tricing rope is to be calculated on the basis of the less than 14 times the towrope diameter.
holding capacity of the tricing winch and a utility

new D.5.2.3
factor K = 2,5.

new D.4.5 5.2.4 The length of the winch drum is to be such
that at least 50 m of the towrope can be wound up in
5. Towing winches the first layer.

new D.5.2.4
5.1 Arrangement and control

5.1.1 The towing winch, including towrope guiding 5.2.5 To ensure security of the rope end fastening,
equipment, has to be arranged such as to guarantee at least 3 dead turns shall remain on the drum.
safe guiding of the towrope in all directions according
new D.5.2.5
to 3.5.2.

new D.5.1.1 5.2.6 At the ends, drums shall have disc sheaves
whose outer edges shall surmount the top layer of the
5.1.2 The winch shall be capable of being safely rope at least by 2,5 rope diameters, if no other means
operated from all control stands. Apart from the con- is provided to prevent the rope from slipping off the
trol stand on the bridge, at least one additional control drum.
stand has to be provided on deck. From each control
stand the winch drum shall be freely visible; where
new D.5.2.6
this is not ensured, the winch shall be provided with a
self-rendering device. 5.2.7 If a multi-drum winch is used, then each
winch drum shall be capable of independent operation.

new D.5.1.2

new D.5.2.7
5.1.3 Each control stand has to be equipped with
suitable operating and control elements. The arrange- 5.2.8 Each towing winch drum shall have sufficient
ment and the working direction of the operating ele- capacity to stow the length of the provided towrope.
ments have to be analogous to the direction of motion
of the towrope. 5.2.3 to 5.2.5 are not applicable to towropes of austen-
itic steels and fibre ropes. In case these towrope mate-

new D.5.1.3 rials are utilized, dimensioning of the wind drum is
subject to GL approval.
5.1.4 Operating levers shall, when released, return
into the stop position automatically. They shall be
new D.5.2.8
capable of being secured in the stop position.
5.3 Holding capacity / dimensioning

new D.5.1.4

5.1.5 It is recommended that, on vessels for ocean 5.3.1 The holding capacity of the towing winch
towage, the winch is fitted with equipment for measur- (towrope in the first layer) shall correspond to 80 % of
ing the pulling force in the towrope. the minimum breaking load Fmin of the towrope.

new D.5.1.5
new D.5.3.1

5.1.6 If, during normal operating conditions, the 5.3.2 When dimensioning the towing winch com-
power for the towing winch is supplied by a main ponents, which - with the brake engaged - are exposed
engine shaft generator, another generator shall be to the pull of the towrope (rope drum, drum shaft,
available to provide power for the towing winch in brakes, foundation frame and its fastening to the
case of main engine or shaft generator failure. deck), a design tractive force equal to the holding
capacity is to be assumed. When calculating the drum

new D.5.1.6
shaft the dynamic stopping forces of the brakes have
to be considered. The drum brake shall not give way
5.2 Winch drum under this load.
5.2.1 The towrope shall be fastened on the winch
new D.5.3.2
drum by a breaking link.

new D.5.2.1 5.4 Brakes

5.2.2 The winch drum shall be capable of being 5.4.1 If the drum brakes are power-operated, man-
declutched from the drive. ual operation of the brake shall be provided addition-
ally.

new D.5.2.2

new D.5.4.1
Chapter 1 Section 25 C Tugs I - Part 1
Page 25–6 GL 2012

5.4.2 Drum brakes shall be capable of being 6.1.1.2 When towing hooks are provided with a
quickly released from the control stand on the bridge, pneumatic slip device, both the pneumatic and the
as well as from any other control stand. The quick mechanical slip device required by 3.4 have to be
release shall be possible under all working conditions, tested according to 6.1.1.1.
including failure of the power drive.

new D.6.1.1.2

new D.5.4.2
6.1.1.3 Also towing hooks with a hydraulic slip de-
5.4.3 The operating levers for the brakes are to be vice have to be tested according to 6.1.1.1, but the slip
secured against unintentional operation. device itself need not be subjected to the test load. If a
cylinder tested and approved by GL is employed as a

new D.5.4.3 loaded gear component, during the load test the cylin-
der may be replaced by a load transmitting member
5.4.4 Following operation of the quick release not pertaining to the gear, the operability of the gear
device, normal operation of the brakes shall be re- being restored subsequently. The operability of the
stored immediately. slip device has to be proved with the towrope loosely
resting on the hook.

new D.5.4.4

new D.6.1.1.3
5.4.5 Following operation of the quick release
device, the winch driving motor shall not start again 6.1.2 Certification and stamping of towing hook
automatically.
Following each satisfactory testing at manufacturer's,

new D.5.4.5 a Certificate (F 186) will be issued by the attending
surveyor and shall be handed on board, together with
5.4.6 Towing winch brakes shall be capable of the towing hook.
preventing the towrope from paying out when the
vessel is towing at the design force T and shall not be
new D.6.1.2
released automatically in case of power failure.
6.1.3 Towing winches

new D.5.4.6
6.1.3.1 The winch power unit has to be subjected to a
test bed trial at the manufacturer's. A works test cer-
5.5 Tricing winches
tificate has to be presented on the occasion of the final
inspection of the winch, see 6.2.4.
5.5.1 Control stands for the tricing winches have to
be located at safe distance off the sweep area of the
new D.6.1.3.1
towing gear. Apart from the control stands on deck, at
least one other control stand shall be available on the 6.1.3.2 Components exposed to pressure are to be
bridge. pressure-tested to a test pressure PD of

new D.5.5.1 PD = 1, 5 ⋅ p

5.5.2 Tricing winches have to be suitably dimen- where

sioned depending on Fmin of the tricing rope. For op-
eration of the tricing winch, perfect transmission of p = admissible working pressure [b]
orders has to be safeguarded. For tricing ropes, see
= opening pressure of the safety valves
4.5.
However, with working pressures exceeding 200 [b],

new D.5.5.2
the test pressure need not be higher than p + 100 [b].

6. Testing Tightness tests are to be carried out at the relevant

components.
6.1 Workshop testing
new D.6.1.3.2

6.1.1 Towing hook and slip device 6.1.3.3 Upon completion, towing winches have to be
subjected to a final inspection and an operational test
6.1.1.1 Towing hooks with a mechanical slip device, to the rated load. The hauling speed has to be deter-
the movable towing arm and other load transmitting mined during an endurance test under the rated
elements have to be subjected to a test force PL with tractive force. During these trials, in particular the
the aid of an approved testing facility. In connection braking and safety equipment shall be tested and ad-
with this test, the slip device shall be tested likewise; justed.
the release force has to be measured and shall not
exceed 150 N, see 3.3. The brake has to be tested to a test load equal to the
rated holding capacity, but at least equal to the bollard

new D.6.1.1.1 pull.
I - Part 1 Section 25 C Tugs Chapter 1
GL 2012 Page 25–7

If manufacturers do not have at their disposal the 6.2.5 Test of towing winches on board
equipment required, a test confirming the design
After installation on board, the safe operation of the
winch capacity, and including adjustment of the over-
winch(es) from all control stands has to be checked; it
load protection device, may be carried out after instal-
has to be proved that in both cases, with the drum
lation on board, see 6.2.5.
braked and during hauling and releasing, the respec-
In that case only the operational trials without apply- tive quick-release mechanism for the drum operates
ing the prescribed loads will be carried out at the well. These checks may be combined with the Bollard
manufacturers. Pull Test, see 6.2.2.

new D.6.1.3.3 The towing winch has to be subjected to a trial during

the bollard pull test to a test load corresponding to the
6.1.4 Accessory towing gear components, holding power of the winch.
Towropes
new D.6.2.4
6.1.4.1 Accessories subjected to towing loads, where 6.3 Recurrent tests of towing gear
not already covered by 6.1.1.1, shall generally be
tested to test force PL at the manufacturer The following tests will be applied to all tugs classed
by GL unless otherwise required by the Administra-

new D.6.1.4.1 tion.
6.1.4.2 For all accessories Test Certificates, Form The Surveyor certifies the satisfactory recurrent test in
LA 3, and for the towrope, Form LA 4, have to be Part C of Form F 186.
submitted.
new D.6.3.1

new D.6.1.4.2
6.3.1 Towing hooks
6.1.4.3 GL reserve the right of stipulating an endur-
6.3.1.1 The functional safety of towing hook and slip
ance test to be performed at towing gear components,
device shall be checked by the ship's master at least
where considered necessary for assessment of their
once a month.
operability.

new D.6.3.2.1

new D.6.1.4.3
6.3.1.2 Following initial testing on board, towing
6.2 Initial testing of towing gear on board and hooks with mechanical and/or pneumatic slip devices
bollard pull test have to be removed every 2,5 years, thoroughly exam-
ined and exposed to test force PL on a recognised
6.2.1 The installed towing gear has to be tested on testing facility. Upon reinstallation of the hook on the
the tug using the bollard pull test to simulate the tow- tug, the slip device has to be subjected to an opera-
rope pull. tional trial by releasing the hook without load. The
release forces at the hook and at the bridge have to be

new D.6.2.1 measured.
For avoiding dismounting of these towing hooks, the
6.2.2 Bollard pull test
test force PL can also be produced by fastening in
In general a bollard pull test will be carried out before front of the first tug towed to the bollard, the hook of
entering into service of the vessel. The test can be which is intended to be tested, another tug with a
witnessed and certified by GL, see VI – Additional design force T which is sufficient to jointly reach the
Rules and Guidelines, Part 11 – Other Operations and required test force PL according to Table 25.1. Slip-
Systems, Chapter 1 – Guidelines for Ocean Towage. ping has to be effected whilst both tugs are pulling
with full test force.

new D.6.2.2

new D.6.3.2.2
6.2.3 For all towing hooks (independent of the 6.3.1.3 Following initial testing on board, towing
magnitude of the test force PL), the slip device has to hooks with hydraulic slip device are to be subjected to
be tested with a towrope direction of 60 degrees to- a functional test on board every 2,5 years. They are
wards above against the horizontal line, under the ready for operation with the towrope loosely resting
towrope pull T. on the hook. The release forces required at the hook

new D.6.2.3 and at the bridge have to be measured. Additionally all
components are to be thoroughly examined. Every 5
years the towing hook has to be pulled against a bol-
6.2.4 The Surveyor certifies the initial board test by
lard.
an entry into the Test Certificate for Towing Hooks
(Form F 186).
new D.6.3.2.3

new D.6.2.3
Chapter 1 Section 25 F Tugs I - Part 1
Page 25–8 GL 2012

6.3.1.4 Particular attention has to be paid to the bi is the breadth of the superstructure tier "i", consid-
proper functioning of all gear components. ering only tiers with a breadth greater than B/4.

new D.6.3.2.4
new F.1

2. General requirements
D. Steering gear/Steering arrangement
2.1 The equipment of tugs for restricted service
areas is to be determined as for vessels in the RSA (20)
1. Steering stability or RSA (50) range, see Section 18, A.3. For tugs in
the service range RSA (SW), see Section 30, E.
Steering stability, i.e. stable course maintaining capa-
bility of the tug, shall be ensured under all normally
new F.2.1
occurring towing conditions. Rudder size and rudder
force shall be suitable in relation to the envisaged 2.2 For tugs engaged only in berthing operations,
towing conditions and speed. one anchor is sufficient, if a spare anchor is readily

new E.1 available on land.

new F.2.2
2. Rudder movement
2.3 The stream anchor specified in Section 18,
Regarding the time to put the rudder from one extreme Table 18.2 is not required for tugs.
position to the other, the requirements of the GL Rules
for Machinery Installations (I-1-2), Section 14, A.
new F.2.3
shall be observed for tugs exceeding 500 gross tons.
Special rudder arrangements may be considered in the
3. Tugs operating as pusher units
particular case, see also 4.
The anchoring equipment for tugs operating as pusher

new E.2
units will be considered according to the particular
service. Normally, the equipment is intended to be
3. Tugs operating as pusher units used for anchoring the tug alone, the pushed unit be-
ing provided with its own anchoring equipment.
For tugs operating as pusher units, the steering gear is
to be designed so as to guarantee satisfying steering
new F.3
characteristics in both cases, tug alone and tug with
pushed object.

new E.3
F. Weather tight integrity and stability
4. Special steering arrangements
1. Weather deck openings
Steering units and arrangements not explicitly covered
by the Rules mentioned above, and combinations of 1.1 Openings (skylights) above the machinery
such units with conventional rudders, will be consid- space shall be arranged with coamings not less than
ered from case to case. 900 mm high, measured from the upper deck. Where

new E.4 the height of the coaming is less than 1,8 m, the casing
covers are to be of specially strong construction, see
also G.1.

new G.1.1
E. Anchoring/mooring equipment
1.2 The head openings of ventilators and air
1. Equipment numeral pipes are to be arranged as high as possible above the
The equipment with anchors and chains as well as the deck.
recommended towropes of tugs for unrestricted ser-
new G.1.2
vice is to be determined according to Section 18, B.
However, for the determination of the equipment
1.3 For companionways to spaces below deck to
numeral the term 2 ⋅ h ⋅ B may be substituted by the be used while at sea, sills with a height not less than
term 600 mm shall be provided. Watertight steel doors are
to be provided which can be opened/closed from ei-
2 ( a ⋅ B + Σ h i ⋅ bi )
ther side.
where
new G.1.3
I - Part 1 Section 25 H Tugs Chapter 1
GL 2012 Page 25–9

1.4 Deck openings shall be avoided in the sweep G. Escape routes and safety measures
area of the towing gear, or else be suitably protected.

new G.1.4 1. Engine room exit

In the engine room an emergency exit is to be pro-
vided on or near the centerline of the vessel, which
2. Stability can be used at any inclination of the ship. The cover
shall be weather tight and is to be capable of being
2.1 The intact stability shall comply with the opened easily from outside and inside. The axis of the
following requirements: cover is to run in athwart ship direction.

new H.1
– the intact stability requirement of the Interna-
tional Code of Intact Stability (2008 IS Code),
Chapter A 2 2. Companionways
Companionways to spaces below deck see F.1.3.
– alternatively if applicable, the intact stability
requirement of the 2008 IS Code, Chapter B.2.4
new H.2

new G.2.1
3. Rudder compartment
Where, for larger ocean going tugs, an emergency exit
2.2 Additionally, the intact stability shall comply is provided from the rudder compartment to the upper
with one of the following requirements: deck, the arrangement, sill height and further details
shall be designed according to the requirements of F.1,
– The residual area between a righting lever curve particularly F.1.4.
and a heeling lever curve developed from 70 %
of the maximum bollard pull force acting in 90°
new H.3
to the ship-length direction should not be less
than 0,09 mrad. The area has to be determined 4. Access to bridge
between the first interception of the two curves
and the second interception or the angle of down Safe access to the bridge is to be ensured for all an-
flooding whichever is less. ticipated operating and heeling conditions, also in
heavy weather during ocean towage.
– Alternatively, the area under a righting lever

new H.4
curve should not be less than 1,4 times the area
under a heeling lever curve developed from
70 % of the maximum bollard pull force acting 5. Safe handling of towing gear
in 90° to ship-length direction. The areas to be
See requirements under C.1, C.3 and C.5.
determined between 0° and the 2nd intercep-
tion or the angle of down flooding whichever is
less. 6. Fire safety

new G.2.2 6.1 Structural fire protection measures shall be as

outlined in Section 22, as applicable according to the
size of the vessel. The fire fighting equipment shall
2.3 The heeling lever curve should be derived by conform to the GL Rules for Machinery Installations
using the following formula: (I-1-2), Section 12, as applicable.

0, 071 ⋅ T ⋅ z h ⋅ cos Θ
new H.5.1

bh = [m]
D
6.2 Additional or deviating regulations of the
bh = heeling arm [m] competent Administration may have to be observed.

new H.5.2
T = maximum bollard pull [kN]

zh = vertical distance [m] between the working

point of the towrope and the centre of the
propeller H. Additional Requirements for Active Escort
Tugs
D = loading condition displacement [t]
1. Scope, application
Θ = heeling angle [°]
1.1 The following requirements apply to vessels

new G.2.3 specially intended for active escort towing. This in-
Chapter 1 Section 25 H Tugs I - Part 1
Page 25–10 GL 2012

cludes steering, braking and otherwise controlling a 4. Definitions

vessel in restricted waters during speeds of up to
10 knots by means of a permanent towline connection 4.1 Active Escort Tug is a tug performing the
with the stern of the escorted vessel, see 4.3. active escort towing.

1.2 The requirements for the notation TUG given
new I.2.1
in A. to G. are also valid, if applicable, for Active
Escort Tugs. 4.2 Assisted vessel is the vessel being escorted
by an Active Escort Tug.

new A.1

new I.2.2
2. Classification, notations
4.3 Indirect towing is a typical manoeuvre of the
2.1 Ships built in accordance with the following re- Active Escort Tug where the maximum transverse
quirements will have the Notation ACTIVE ESCORT steering force is exerted on the stern of the assisted
TUG affixed to their Character of Classification. vessel while the Active Escort Tug is at an oblique
angular position. The steering force TEy [kN] is pro-

I-0, Section 2, Table 2.9 vided by the hydrodynamic forces acting on the Ac-
tive Escort Tug's hull, see Fig. 25.1.
3. Characteristics of Active Escort Tugs

new I.2.3
3.1 The following escort characteristics are to be
determined by approved full scale trials: 4.4 Test speed Vt [kn] is the speed of advance
(through the water) of the assisted vessel during full
– maximum steering force TEy [kN] at a test scale trials.
speed of advance Vt [kn], normally 8 to 10 knots

new I.2.4
– manoeuvring time t [s]
4.5 The manoeuvring time t [s] is the time
– manoeuvring coefficient K = 31 / t [–] or 1,
needed for the Active Escort Tug to shift in indirect
whichever is less
towing from an oblique angular position at the stern of

new I.1.1 the assisted vessel to the mirror position on the other
side, see Fig.25.1. The length of the towline during
3.2 A test certificate indicating the escort character- such a manoeuvre should not be less than 50 m and
istics is issued on successful completion of such trials. the towline angle need not be less than 30°.

new I.1.2
new I.2.5
I - Part 1 Section 25 H Tugs Chapter 1
GL 2012 Page 25–11

assisted vessel TEy = steering force

TEx = braking force
TE = towrope pull
a = towline angle
Vt b = oblique angle

Vt = speed of advance
during test

TEy

TEx TE
mirror b Active
position Escort Tug

Fig. 25.1 Typical working mode of an Active Escort Tug

5. Documentation

new I.3.1.1
The following documents shall be submitted in addi-
tion to those of A.3.1: 6.1.2 Freeboard is to be provided in such a way,
– GL material certificates for all load transmitting that excessive trim at higher heeling angles is avoided.
elements (e.g. motor, drive) of the towing winch
new I.3.1.2
– circuit diagrams of the hydraulic and electrical 6.1.3 A bulwark is to be fitted all around the
systems of the towing winches in triplicate for weather deck.
approval

new I.3.1.3
– one copy of a description of the towing winch
including the safety devices
6.2 Towing winch
– preliminary calculation of the maximum steering
force TEy [kN] and maximum towrope pull TE 6.2.1 The equipment for measuring the pulling
[kN] at the intended test speed Vt [kn] with indi- force in the towrope, recommended in C.5.1.5, is to be
cation of propulsion components necessary for provided in any case for towing winches of Active
balancing the Active Escort Tug at an oblique an- Escort Tugs.
gular position at the stern of the assisted vessel

I-0, Section 2, D.2
new I.3.2.1

6. Arrangement and Design 6.2.2 In addition to the requirements given in C.5.

towing winches of escort tugs are to be fitted with a
6.1 Hull load damping system which prevents overload caused
by dynamic impacts in the towrope.
6.1.1 The hull of the Active Escort Tug is to be
designed to provide adequate hydrodynamic lift and The towing winch shall pay out the towrope controlled
drag forces when in indirect towing mode. Hydrody- when the towrope pull exceeds 50 % of the minimum
namic forces, towline pull and propulsion forces shall breaking force Fmin of the towrope. Active escort tow-
be in balance during active escort towing thereby ing is always carried out via the towing winch, with-
minimising the required propulsion force itself. out using the brake on the towing winch's rope drum.

new I.3.2.2
Chapter 1 Section 25 H Tugs I - Part 1
Page 25–12 GL 2012

– calculated maximum steering force TEy [kN]

6.2.3 The towing winch shall automatically spool a
slack towrope. The requirement C.5.2.4 may be
new I.5.1.1
waived, if an impeccable spooling of the towrope
under load is guaranteed by design measures (e.g. 8.1.2 Full scale trials shall be carried out in favour-
spooling device). able weather and sea conditions which will not sig-
nificantly influence the trial results.

new I.3.2.3

new I.5.1.2
6.3 Propulsion
8.1.3 The size of the assisted vessel shall be suffi-
In case of loss of propulsion during indirect towing the ciently large to withstand the transverse steering
remaining forces are to be so balanced that the result- forces of the tug without using too large rudder angles.
ing turning moment will turn the Active Escort Tug to
a safer position with reduced heel.
new I.5.1.3

new I.3.3 8.2 Recordings
7. Stability of Active Escort Tugs
At least the following data are to be recorded continu-
Proof of stability has to be shown by using the heeling ously during the trial for later analysis:
lever curve calculated by the following formula:
Assisted vessel:
TE ⋅ z h ⋅ cos Θ
bh = [m] – position
9,81 ⋅ D
– speed over ground and through the water
TE = maximum towrope pull [kN]
– heading

new I.4
– rudder angle
8. Full Scale Trials – angle of towline
– wind (speed and direction), sea-state
8.1 Procedure
Active Escort Tug:
8.1.1 A documented plan, describing all parts of
the trial shall be submitted for approval before com- – position and speed over ground
mencement of the trials, including:
– heading
– towage arrangement plan
– length, angle β and pull of towrope TE
– data of assisted vessel including SWL of the
strong points – heeling angle
– intended escort test speed
new I.5.2
I - Part 1 Section 26 D Passenger Ships Chapter 1
GL 2012 Page 26–1

Section 26

Passenger Ships

A. General
6. Passenger vessels, which due to their overall
1. The requirements given in Sections 1 – 22 design are only suitable for trade in defined waterways
apply to passenger ships unless otherwise mentioned (e.g. RSA (SW)) may in no case be assigned an ex-
in this Section. tended navigation notation to the Character of Classi-
fication, even if the strength of the hull is sufficient for

new A.1.1
a wider range of service (e.g. RSA (50)). In that event,
this may be expressed in the Certificate by adding the
The various special regulations for passenger ships following note: "The strength of the hull structural
contained in the GL Rules for Machinery Installations elements complies with the service range ...".
(I-1-2), are to be observed.

I-0, Section 2, Table 2.2

I-0, Section 2, Table 2.7

2. A passenger ship as defined in this Section is 7. The terms used in this Section are the same as
a ship carrying more than 12 passengers on board. those of SOLAS as amended.

I-0, Section 2, Table 2.7

3. The Notation PASSENGER SHIP will be B. Documents for Approval

affixed to the Character of Classification of ships com-
plying with the Construction Rules for the carriage In addition to those specified in Section 1, G. the do-
and/or accommodation of passengers and with the cuments according to Section 28, A. are to be submit-
applicable requirements of the Chapters II-1 and II-2 ted. Furthermore, a design load plan is to be submitted
of SOLAS as amended. for the window approval.

I-0, Section 2, Table 2.7

I-0, Section 2, D.2
4. Exemptions from these requirements may be
granted only within the framework of options given
therein and are subject of approval by the competent C. Watertight Subdivision
Administration.

new A.1.2 1. For location of collision bulkhead and stern
tube see Section 11, A.2.
Note

new Section 27, B.
For ships subject to the supervision of the See-
Berufsgenossenschaft, the additional regulations of 2. Openings in watertight bulkheads below the
the valid Schiffssicherheitsverordnung (SSV) and bulkhead deck, see Chapter II-1 Reg. 13 of SOLAS as
Unfallverhütungsvorschriften (UVV) are to be ob- amended.
served.

new A.1.2 Note
new Section 27, B.6

5. Passenger ships will be assigned the symbol

 for characterizing proof of damage stability accord- D. Double Bottom
ing to the relevant requirements. The following data
will be entered into an appendix to the Certificate: A double bottom shall be fitted extending from the
collision bulkhead to the after peak bulkhead, as far as
– code for the specification of the proof of damage this is practicable and compatible with the design and
stability according to the GL Rules for proper working of the ship. The arrangement shall
Classification and Surveys (I-0), Section 2, comply with Chapter II-1 of SOLAS as amended and
C.2.4. Section 28.

I-0, Section 2, C.2.4 and Table 2.1

new Section 27, C.2
Chapter 1 Section 26 I Passenger Ships I - Part 1
Page 26–2 GL 2012

E. Superstructure
new Section 27, B.6.4.17 and B.6.4.18

1. In general the requirements of Section 16

have to be observed. G. Materials for Closures of Openings
The deck loads in cabin areas as defined in Section 4,
C.3.1, may be reduced to: Appropriate materials are to be used only. Materials
with at least 10 per cent breaking elongation are to be
p = 2,5 ⋅ (1 + av) used for the closures of openings in the shell plating,
in watertight bulkheads, in boundary bulkheads of
if a corresponding weight calculation can be provided. tanks, and in watertight decks. Lead and other heat

new B.1 sensitive materials are not to be used for structural
parts whose destruction would impair the watertight-
2. The following minimum thicknesses for ac- ness of the ship and/or the bulkheads.
commodation and superstructure decks have to be ob-
new C
served:
– tmin = 5,0 mm for decks inside
– tmin = 5,5 mm for decks exposed to weather, if H. Cross-Flooding Arrangements
effective sheathing is provided.
For cross-flooding arrangements refer to Section 28, F.

new B.2

I. Pipe Lines
F. Openings in the Shell Plating
1. Where pipes are carried through watertight
1. The number of openings in the shell plating is bulkheads, Chapter II-1 Reg. 12 and 13 of SOLAS as
to be reduced to the minimum compatible with the amended is to be observed.
design and proper working of the ship.

new D.1

new Section 27, B.6.4.1

2. The arrangement and efficiency of the means 2. Where the ends of pipes are open to spaces
for closing any opening in the shell plating shall be below the bulkhead deck or to tanks, the arrangements
consistent with its intended purpose and the position are to be such as to prevent other spaces or tanks from
in which it is fitted and generally to the satisfaction of being flooded in any damage condition. Arrangements
the Administration. will be considered to provide safety against flooding if
pipes which are led through two or more watertight

new Section 27, B.6.4.2 compartments are fitted inboard of a line parallel to
the subdivision load line drawn at 0,2 B from the
3. Arrangement, position and type of sidescut- ship's side (B is the greatest breadth of the ship at the
tles and associated deadlights are to be in accordance subdivision load line level).
with the requirements of Chapter II-1 Reg. 15 of
new D.2
SOLAS as amended and with Regulation 23, ICLL.

new Section 27, B.6.4 3. Where the pipe lines cannot be placed in-
board of the line 0,2 B from the ship's side, the bulk-
4. Doors in the shell plating below the bulkhead head is to be kept intact by the means stated in 4. - 6.
deck are to be provided with watertight closures. Their
new D.3
lowest point is not to be located below the deepest
subdivision load line. The corresponding requirements
of the ICLL (Reg. 21) have also to be observed. Re- 4. Bilge lines have to be fitted with a non-return
garding pilot doors additional requirements are given valve at the watertight bulkhead through which the
in Chapter V Reg. 23 of SOLAS as amended. pipe is led to the section or at the section itself.

new Section 27, B.6.4
new D.4

5. The inboard openings of ash- and rubbish 5. Ballast water and fuel lines for the purpose of
shoots, etc., are to be fitted with efficient covers. If the emptying and filling tanks have to be fitted with a
inboard openings are situated below the margin line, shutt-off valve at the watertight bulkhead through
the covers are to be watertight and, in addition, auto- which the pipe leads to the open end in the tank. These
matic non-return valves are to be fitted in the shoots shut-off valves shall be capable of being operated from
above the deepest subdivision load line. Equivalent a position above the bulkhead deck which is accessible
arrangements may be approved. at all times and are to be equipped with indicators.
I - Part 1 Section 26 J Passenger Ships Chapter 1
GL 2012 Page 26–3

new E.1

new D.5
1.1 Ship safety relevant areas, such as all tiers of
6. Where overflow pipes from tanks which are front walls of superstructures, wheelhouse and others
situated in various watertight compartments are con- as may be defined.
nected to a common overflow system, they shall either
be led well above the bulkhead deck before they are – tests according to ISO 1751 and ISO 3903 as
connected to the common line, or means of closing are appropriate. Window sizes not covered by ISO
to be fitted in the individual overflow lines. The standards are to be tested at four times design
means of closing shall be capable of being operated pressure.
from a position above the bulkhead deck which is

new E.1.1
accessible at all times. These means of closing are to
1.2 Side walls and aft facing walls of superstruc-
be fitted at the watertight bulkhead of the compart-
ment in which the tank is fitted and are to be sealed in tures from the 2nd to the 4th tier above freeboard deck.
the open position. – no test requirements regarding weathertightness
These means of closing may be omitted, if pipe lines – test for structural strength according ISO 1751
pass through bulkheads at such a height above base and ISO 3903 as appropriate at four times de-
line and so near the centre line that neither in any sign pressure.
damaged condition nor in case of maximum heeling
occurring in intermediate conditions, they will be
new E.1.2
below the water line.

new D.6 1.3 Side walls and aft facing walls of superstruc-
tures 5th tier and upwards above freeboard deck.
7. The means of closing described in 4. and 5. – no test requirements regarding weathertightness
should be avoided where possible by the use of suita-
bly installed piping. Their fitting may only be ap- – test for structural strength according ISO 1751
proved by GL in exceptional circumstances. and ISO 3903 as appropriate at two times design
pressure.

new D.7
All design pressures for the dimensioning of side scuttles
and windows on the basis of ISO 1751 and ISO 3903 are
to be in accordance with Section 21, C.2. However, the
J. Side Scuttles and Windows design pressure for the 5th tier and higher for all areas,
except unprotected fronts, can be set to 3,6 kN/m2.
1. Depending on the arrangement of side scut-
tles and windows, the following tests shall be per-
new E.1.3
formed.
I - Part 1 Section 27 B Special Purpose Ships Chapter 1
GL 2012 Page 27–1

Section 27

Special Purpose Ships

A. General
3.2 Notation
1. Application
Special purpose ships, built in accordance with the
1.1 Special purpose ships are subject to the re- requirements of this Section will have the Notation
quirements of Sections 1 – 21 and 26 unless otherwise SPECIAL PURPOSE SHIP affixed to their Charac-
mentioned in this Section. ter of Classification.

new I-0, Section 2, Table 2.9

I-0, Section 2, Table 2.9
1.2 A special purpose ship is a ship as defined in
the Code of Safety for Special Purpose Ships (2008
SPS Code), as amended.

new I-0, Section 2, Table 2.9 B. Documents for Approval

2. Structural fire protection The following documents are to be submitted in addi-

The Structural Fire Protection shall be in accordance tion to those specified in Section 1, G.:
with 2008 SPS Code, as amended, Chapter 6 – Fire
Protection
– drawings showing the external openings and the

new I-0, Section 2, Table 2.9 closing devices thereof– drawings showing
the watertight subdivision as well as internal
openings and the closing devices thereof
3. Character of Classification and Notation

3.1 Special purpose ships will be assigned the – intact and damage stability calculation in accor-
symbol  for characterizing proof of damage stability dance with SPS Code 2008, as amended
according to SPS Code 2008, as amended. The follow-
ing data will be entered into an appendix to the Cer-
tificate: – damage control plan and damage control booklet
containing all data essential for maintaining the
– Code for the specification of the proof of dam- survival capability
age stability according to the GL Rules for Clas-
sification and Surveys (I-0), Section 2, C.2.4

I-0, Section 2, D.2
– Description of the code

I-0, Section 2, C.2.4 and Table 2.1
I - Part 1 Section 28 B Subdivision and Stability of Cargo Ships and Passenger Ships Chapter 1
GL 2012 Page 28–1

Section 28

Subdivision and Stability of Cargo Ships and Passenger Ships

A. General
– damage control plan and damage control booklet
containing all data essential for maintaining the
1. Application survival capability

The requirements of this Section apply to cargo ships – stability information in accordance with B.
of 500 GT and more and to all passenger ships regard-
I-0, Section 2, D.2
less of length, as well as those ships covered by other
damage stability regulations in conventions or codes.

new Section 28, A.1
B. Onboard Stability Information
Note
1. The Master shall be supplied with such in-
This Section refers to Chapter II-1 of SOLAS as formation satisfactory to the Administration as is
amended and the related Explanatory Notes. Alterna- necessary to enable him by rapid and simple processes
tive arrangements will be accepted for a particular to obtain accurate guidance as to the stability of the
ship or group of ships, if they have been acknowl- ship under varying conditions of service. A copy of
edged by the competent Administration as providing at the stability information shall be furnished to the Ad-
least the same degree of safety. ministration.

covered by new Section 28 The information should include:

covered by new Section 28, B.1.1
2. Character of Classification
1.1 Curves or tables of minimum operational
Ships for which damage stability according to a con- metacentric height GM' versus draught which assure
vention or code has been proven will be assigned the compliance with the relevant intact and damage stabil-
symbol  for characterizing proof of damage stabil- ity requirements, alternatively corresponding curves or
ity. The following data will be entered into an appen- tables of the maximum allowable vertical centre of
dix to the Certificate: gravity KG' versus draught, or with the equivalents of
either of these curves.

I-0, Section 2, Table 2.1

covered by new Section 28, B.1.1
2.1 Code for the specification of the proof of
damage stability according to the GL Rules for Clas- 1.2 Instructions concerning the operation of
sification and Surveys (I-0), Section 2, C.2.4.2. cross-flooding arrangements.

covered by new Section 28, B.1.1
3. Documents for approval
1.3 All other data and aids which might be neces-
The following documents are to be submitted in addi- sary to maintain the required intact stability and stabil-
tion to those specified in Section 1, G.: ity after damage.

– drawings showing the external openings and the
covered by new Section 28, B.1.1
closing devices thereof
1.4 There shall be permanently exhibited, for the
– drawings showing the watertight subdivision as guidance of the officer in charge of the ship, plans
well as internal openings and the closing devices showing clearly for each deck and hold the boundaries
thereof of the watertight compartments, the openings therein
with the means of closure and position of any controls
– damage stability calculation in accordance with thereof, and the arrangements for the correction of any
SOLAS as amended and the related Explanatory list due to flooding. In addition, booklets containing
Notes if applicable the aforementioned information shall be made avail-
able to the ships command.
– damage stability calculations acc. to any other
convention or code which is applicable for the
covered by new Section 28, B.1.1
vessel
Chapter 1 Section 28 D Subdivision and Stability of Cargo Ships and Passenger Ships I - Part 1
Page 28–2 GL 2012

2. The stability information shall show the in- 3. Where a double bottom is required to be fitted
fluence of various trims in cases where the operational the inner bottom shall be continued out to the ship's
trim range exceeds +/-0.5% of LS. sides in such a manner as to protect the bottom to the
turn of the bilge. Such protection will be deemed satis-

covered by new Section 28, B.1.1
factory if the inner bottom is not lower at any part than
a plane parallel with the keel line and which is located
3. All passenger vessels and all cargo vessels not less than a vertical distance h measured from the
with Lc ≥ 80 m excluding those ships covered by other keel line, as calculated by the formula:
damage stability regulations in conventions and codes
have to fulfil the stability requirements of part B-1 of h = B/20
SOLAS as amended. For these ships information re- However, in no case is the value of h to be less than
ferred to in paragraph 1 are determined from considera- 760 mm, and need not be taken as more than
tions related to the subdivision index, in the following 2000 mm.
manner: Minimum required GM' values (or maximum
permissible vertical positions of centre of gravity KG') for
new Section 27, C.2.3
the three draughts ds, dp and dl are equal to the GM' (or
KG' values) of corresponding loading cases used for the 4. Small wells constructed in the double bottom
calculation of survival factor si. in connection with drainage arrangements of holds,
etc., shall not extend downward more than necessary.
For intermediate draughts, values to be used shall be In no case shall the vertical distance from the bottom
obtained by linear interpolation applied to the GM' value of such a well to a plane coinciding with the keel line
only between the deepest subdivision draught and the be less than 500 mm.
partial subdivision draught and between the partial load
line and the light service draught respectively.
new Section 27, C.2.4
Intact stability criteria will also be taken into account by
5. In the case of unusual bottom arrangements in a
retaining for each draught the maximum among mini-
passenger ship or a cargo ship, it shall be demonstrated
mum required GM' values or the minimum of maximum
that the ship is capable of withstanding bottom damages
permissible KG' values for both criteria. If the subdivi-
as specified in Chapter II-1 of SOLAS as amended.
sion index is calculated for different trims, several re-
quired GM' curves will be established in the same way.
new Section 27, C.2.7

covered by new Section 28, B.1.1

4. When curves or tables of minimum opera-

tional metacentric height GM' versus draught are not D. Watertight Bulkheads and Decks
appropriate, the master should ensure that the operat-
ing condition does not deviate from a studied loading 1. For watertight bulkheads Section 11 and for
condition, or verify by calculation that the stability decks Section 7 is to be observed.
criteria are satisfied for this loading condition.
2. The scantlings of watertight bulkheads and

covered by new Section 28, B.1.1 decks, forming the boundaries of watertight compart-
ments assumed flooded in the damage stability analy-
5. The terms used in this Section are the same as sis, shall be based on pressure heights corresponding
those of SOLAS as amended. to 1 m above the deepest final waterline of the damage

covered by new Section 28, B.1.1 cases contributing to the attained subdivision index A.

new Section 11 (pressure height h)

C. Double Bottom 3. The number of openings in watertight subdivi-

sions is to be kept to a minimum compatible with the
1. For all passenger vessels and all cargo vessels design and proper working of the ship. Where penetra-
of 500 GT and more excluding tankers the arrangement tions of watertight bulkheads and internal decks are
shall comply with Chapter II-1 of SOLAS as amended. necessary for access, piping, ventilation, electrical
cables, etc., arrangements are to be made to maintain
Abstract of this Regulation: the watertight integrity. The Administration may per-
mit relaxations in the water tightness of openings above

new Section 27, C.2.1 the freeboard deck, provided that it is demonstrated that
any progressive flooding can be easily controlled and
2. A double bottom shall be fitted extending that the safety of the ship is not impaired.
from the collision bulkhead to the after peak bulkhead,
as far as this is practicable and compatible with the
new Section 27, B.6.1.1
design and proper working of the ship.
4. Doors provided to ensure the watertight integ-

new Section 27, C.2.2 rity of internal openings which are used while at sea are
I - Part 1 Section 28 F Subdivision and Stability of Cargo Ships and Passenger Ships Chapter 1
GL 2012 Page 28–3

to be sliding watertight doors (see the GL Rules for Such openings shall, except for cargo hatch covers, be
Machinery Installations (I-1-2), Section 14) capable of fitted with indicators on the bridge.
being remotely closed from the bridge and are also to

new Section 27, B.3.2
be operable locally from each side of the bulkhead.
Indicators are to be provided at the control position
showing whether the doors are open or closed, and an 2. Openings in the shell plating below the deck
audible alarm is to be provided at the door closure. limiting the vertical extent of damage shall be fitted
The power, control and indicators are to be operable in with a device that prevents unauthorized opening, if
the event of main power failure. Particular attention is they are accessible during the voyage.
to be paid to minimize the effect of control system
new Section 27, B.6.3.3
failure. Each power-operated sliding watertight door
shall be provided with an individual hand-operated 3. Other closing appliances which are kept per-
mechanism. It shall be possible to open and close the manently closed at sea to ensure the watertight integ-
door by hand at the door itself from both sides.
rity of external openings shall be provided with a

new Section 27, B.6.1.2 notice affixed to each appliance to the effect that it is
to be kept closed. Manholes fitted with closely bolted
covers need not be so marked.
5. Access doors and access hatch covers nor-
mally closed at sea, intended to ensure the watertight
new Section 27, B.6.3.4
integrity of internal openings, shall be provided with
means of indication locally and on the bridge showing 4. For openings in the shell plating below the
whether these doors or hatch covers are open or bulkhead deck of passenger ships and the freeboard deck
closed. A notice is to be affixed to each such door or of cargo ships refer to Chapter II-1 SOLAS as amended.
hatch cover to the effect that it is not to be left open.

new Section 27, B.6.4

new Section 27, B.6.1.3

6. Watertight doors or ramps of satisfactory con-

struction may be fitted to internally subdivide large car- F. Cross-Flooding Arrangements
go spaces, provided that the Administration is satisfied
that such doors or ramps are essential. These doors or 1. Where the damage stability calculation re-
ramps may be hinged, rolling or sliding doors or ramps, quires the installation of cross-flooding arrangements
but shall not be remotely controlled, see interpretation in order to avoid high asymmetrical flooding, these
of regulations of Part B-1 of SOLAS Chapter II-1 arrangements shall work automatically as far as possi-
(MSC/Circ. 651). Should any of the doors or ramps be ble. Non-automatic controls for cross-flooding fittings
accessible during the voyage, they shall be fitted with a are to be capable of being operated from the bridge or
device which prevents unauthorized opening. another central location. The position of each closing
device has to be indicated on the bridge and at the

new Section 27, B.6.1.4
central operating location (see also the GL Rules for
Machinery Installations (I-1-2), Section 11, P., and
7. Other closing appliances which are kept per- Electrical Installations (I-1-3), Section 7, H.). The
manently closed at sea to ensure the watertight integri- sectional areas of the cross-flooding fittings are to be
tyof internal openings shall be provided with a notice determined 1 in such a way that the time for equaliza-
which is to be affixed to each such closing appliance to tion does not exceed 10 minutes. Particular attention is
the effect that it is to be kept closed. Manholes fitted to be paid to the effects of the cross-flooding arrange-
with closely bolted covers need not be so marked. ments upon the stability in intermediate stages of

new Section 27, B.6.1.5 flooding.

8. For openings in watertight bulkheads below 2. Suitable information concerning the use of
the bulkhead deck in passenger ships refer to Chapter the closing devices installed in cross-flooding ar-
II-1 of SOLAS as amended. rangements shall be supplied to the master of the ship.

covered by new Section 28, B.8.1.2 and C.4.7.2

E. External Openings

1. All external openings leading to compart-

ments assumed intact in the damage analysis, which
are below the final damage waterline, are required to
be watertight.

new Section 27, B.6.3.1 1 Following the Res. MSC.245(83).
Chapter 1 Section 28 F Subdivision and Stability of Cargo Ships and Passenger Ships I - Part 1
Page 28–4 GL 2012

3. When determining the bulkhead scantlings of

tanks, connected by cross-flooding arrangements, the
increase in pressure head at the immerged side that
may occur at maximum heeling in the damaged condi-
tion shall be taken into account.

new Section 12 A.1.4

I - Part 1 Section 29 C Work Ships Chapter 1
GL 2012 Page 29–1

Section 29

Work Ships

A. General
– drawings showing the watertight subdivision as
well as internal openings and the closing devices
1. Validity, Class symbols thereof (3-fold)

1.1 Work vessels and vessels to maintain the – damage control plan containing all data essential
supply/replenishment of islands shall comply with the for maintaining the survival capability (at least
requirements of this Section. 3-fold)

new A.1 – stability information (at least 3-fold)

I-0, Section 2, D.2
1.2 Ships intended for supply/replenishment of
islands and ships of similar use which comply with
the requirements of this Section will have the Notation
SUPPLY VESSEL affixed to their Character of Clas- B. Shell Plating, Frames
sification.

new I-0, Section 2, Table 2.9 1. Shell plating

1.3 Working ships (e.g. buoy tender, etc.) which 1.1 The thickness of the side shell plating includ-
comply with the requirements of this Section will have ing bilge strake is not to be less than:
the Notation WORK SHIP affixed to their Character
of Classification. t = 7 + 0,04 L [m]

new I-0, Section 2, Table 2.9
new B.1.1

1.2 Flat parts of the ship's bottom in the stern
1.4 The requirements of Sections 1 – 22 apply, area are to be efficiently stiffened.
unless otherwise mentioned in this Section.

new B.1.2

new A.1
1.3 Where the stern area is subjected to loads due to
1.5 For vessels which are intended to supply and heavy cargo, sufficient strengthenings are to be provided.
support offshore installations, and vessels intended for
new B.1.3
offshore towing operations, well stimulation and other
offshore services the requirements of the GL Rules for 2. Frames
Hull Structures (I-6-1) have to be applied.
The section modulus of main and 'tweendeck frames is

new A.2.1 to be increased by 25 % above the values required by
Section 9.
Note

new B.2
For supply vessels which shall transport limited
amounts of hazardous and/or noxious liquid sub-
stances in bulk, the IMO-Resolution A.673 (16), shall C. Weather Deck
be observed. (See also the GL Rules for Chemical
Tankers (I-1-7), Section 20.) 1. The scantlings of the weather deck are to be

new A.2.2 based on the following design load:
p = p L + c ⋅ pD [kN/m 2 ]
2. Documents for approval
pL = cargo load as defined in Section 4, C.1.
The following documents are to be submitted in addi-
tion to those specified in Section 1, G.: pLmin = 15 kN/m2
pD = deck load according to Section 4, B.1.
– drawings showing the external openings and the
closing devices thereof (3-fold) c = 1,28 – 0,032 ⋅ pL for pL < 40 kN/m2
Chapter 1 Section 29 F Work Ships I - Part 1
Page 29–2 GL 2012

= 0 for pL ≥ 40 kN/m2 D. Superstructures and Deckhouses

new C.1 1. The plate thickness of the external boundaries

of superstructures and deckhouses is to be increased
2. The thickness of deck plating is not to be by 1 mm above the thickness as required in Section
taken less than 8,0 mm. In areas for the stowage of 16, C.3.2.
heavy cargoes the thickness of deck plating is to be
suitably increased.
new D.1

new C.2
2. The section modulus of stiffeners is to be
increased by 50 % above the values as required in
3. On deck stowracks for deck cargo are to be Section 16, C.3.1.
fitted which are effectively attached to the deck.

new D.2
The stowracks are to be designed for a load at an angle
of heel of 30°. Under such loads the following stress
values are not to be exceeded:
120 E. Access to Spaces
bending stress: σb ≤ [N/mm 2 ]
k
1. Access to the machinery space
80
shear stress: τ ≤ [N/mm 2 ]
k 1.1 Access to the machinery space should, if
k = material factor according to Section 2, B.2. possible, be arranged within the forecastle.

new C.3 Any access to the machinery space from the exposed
cargo deck is to be provided with two weathertight
closures.
4. The thickness of the bulwark plating is not to
be less than 7,5 mm.
new E.1.1

new C.4 1.2 Due regard is to be given to the position of
the machinery space ventilators. Preferably they
5. Air pipes and ventilators are to be fitted in should be fitted in a position above the superstructure
protected positions in order to avoid damage by cargo deck or above an equivalent level.
and to minimize the possibility of flooding of other
new E.1.2
spaces.

new C.5 2. Access to spaces below the exposed cargo deck
Access to spaces below the exposed cargo deck shall
6. Due regard is to be given to the arrangement preferably be from a position within or above the
of freeing ports to ensure the most effective drainage superstructure deck.
of water trapped in pipe deck cargoes. In vessels oper-
ating in areas where icing is likely to occur, no shut-
new E.2
ters are to be fitted in the freeing ports.

new C.6 F. Equipment

Depending on service area and service conditions it

may be necessary to choose the anchor chain cable
thicker and longer as required in Section 18, D.

new F
I - Part 1 Section 30 C Ships for Sheltered Water Service Chapter 1
GL 2012 Page 30–1

Section 30

Ships for Sheltered Water Service

A. General
5. The thickness of the shell plating is nowhere
1. The requirements given in Sections 1 – 22 to be less than 3,5 mm.
apply to ships sailing in sheltered shallows unless
otherwise mentioned in this Section.
new C.1

new A.1
6. Strengthening of the bottom forward accord-
2. Ships sailing in sheltered shallows complying ing to Section 6, E. is not required.
with the requirements of this Section will have the
Notation RSA (SW) affixed to the Character of Classi-
new C.2.4
fication.

I-0, Section 2, Table 2.2
7. The plate thickness of sides of superstruc-
tures is to be determining according to 4. and 5. analo-
3. The deck load is to be taken as p = 6 kN/m2 gously.
unless a greater load is required by the Owner.

new B
new C.3
C. Watertight Bulkheads and Tank Bulk-
heads

B. Shell Plating
1. The scantlings of watertight bulkheads are to
1. The thickness of bottom plating within 0,4 L be determined according to Section 11.
amidships is not to be less than:
The plate thickness need not be greater than the mid-
a L ⋅ T ship thickness of the side shell plating at the corre-
t = 1,3 [mm] sponding frame spacing.
a0 H
The thickness is, however, not to be less than the fol-
L lowing minimum values:
a0 = + 0, 48 [m]
500
for the lowest plate strake

new C.2.1

t min = 3,5 mm
2. For ships having flat bottoms the thickness is
to be increased by 0,5 mm.
for the remaining plate strakes

new C.2.2
t min = 3, 0 mm
3. The thickness of the side shell plating within
0,4 L may be 0,5 mm less than the bottom plating
according to 1.
new D.1

new C.3
2. The scantlings of tank bulkheads and tank
walls are to be determined according to Section 12.
4. The thickness within 0,05 L from the forward The thickness of plating and stiffener webs is not to be
and aft end of the length L may be 1,0 mm less than less than 5,0 mm.
the value determined according to 1.

new C.2.3
new D.2
Chapter 1 Section 30 E Ships for Sheltered Water Service I - Part 1
Page 30–2 GL 2012

D. Deck Openings on decks in Pos. 2 = 380 mm

new E.2.2
1. Hatchways

1.1 The height above deck of hatchway coamings

is not to be less than: E. Equipment
on decks in Pos. 1 = 600 mm
1. The equipment of anchors, chain cables and
on decks in Pos. 2 = 380 mm recommended ropes is to be determined according to
See also Section 1, H.6.3. Section 18.
The anchor mass may be 60 % of the value required

new E.1.1
by Table 18.2. The chain diameter may be determined
according to the reduced anchor mass.
1.2 The thickness of coamings is to be deter-
mined according to the following formulae:
new F.1 and F.2
longitudinal coaming:
2. For anchor masses of less than 120 kg, the
ℓ chain cable diameter of grade K1 steel is to be calcu-
tℓ = 4,5 + [mm]
6 lated according to the following formula:
transverse coaming: d = 1,15 P [mm]
b
tq = 2, 75 + [mm] P = anchor mass [kg]
2
Short link chain cables are to have the same breaking
ℓ = length of hatchway [m] load as stud link chain cables.

new E.1.2
new F.3
b = breadth of hatchway [m]
3. If an anchor mass of less than 80 kg has been
1.3 For hatch covers the requirements of Section determined, only one anchor is required and the chain
17 apply. cable length need not exceed 50 % of the length re-
quired by Table 18.2.

new E.1.3

new F.4
2. Casings, companionways
4. The length of the ropes is recommended to be
2.1 The height of machinery and boiler room 50 per cent of the length given in Table 18.2 1.
casings is not to be less than 600 mm, their thickness
is not to be less than 3 mm. Coamings are not to be
new F.5
less in height than 350 mm and they are not to be less
in thickness than 4 mm. 5. Ships sailing in sheltered shallows the

new E.2.1 equipment of which is in accordance with the require-
ments of this Section will have the index RSA (SW)
affixed to the Register Number.
2.2 The height above deck of companionway
coamings is not to be less than:
on decks in Pos. 1 = 600 mm 1 See also Section 18, F.
I - Part 1 Section 31 B Barges and Pontoons Chapter 1
GL 2012 Page 31–1

Section 31

Barges and Pontoons

A. General

1. Definitions
B. Longitudinal Strength
1.1 Barges as defined in this Section are un-
manned or manned vessels, normally without self- 1. The scantlings of longitudinal members of
propulsion, sailing in pushed or towed units. The ra- barges and pontoons of 90 m and more in length are to
tios of the main dimensions of barges are in a range be determined on the basis of longitudinal strength
usual for seagoing ships; their construction complies calculations. For barges of less than 90 m in length,
with the usual construction of seagoing ships; their the scantlings of longitudinal members are to be gen-
cargo holds are suitable for the carriage of dry or liq- erally determined according to Section 7, A.4.
uid cargo.

new B.1 and B.2

new A.3
2. The midship section modulus may be 5 %
1.2 Pontoons as defined in this Section are un- less than required according to Section 5.
manned or manned floating units, normally without
self-propulsion. The ratios of the main dimensions of
new B.3
pontoons deviate from those usual for seagoing ships.
Pontoons are designed to usually carry deck load or 3. The scantlings of the primary longitudinal
working equipment (e.g. lifting equipment, rams etc.) members (strength deck, shell plating, deck longitudi-
and have no holds for the carriage of cargo. nals, bottom and side longitudinals, etc.) may be 5 %

new A.3 less than required according to the respective preced-
ing Sections of this Chapter. The minimum thickness
and critical thickness specified in these Sections are,
2. Validity however, to be adhered to.
The requirements given in Section 1 – 24 apply to
new B.4
barges and pontoons unless otherwise mentioned in
this Section. 4. Longitudinal strength calculations for the

new A.1 condition "Barge, fully loaded at crane" are required,
where barges are intended to be lifted on board ship
by means of cranes. The following permissible
3. Character of Classification stresses are to be observed:

3.1 Vessels built in accordance with the require- 150

bending stress: σb = [N/mm 2 ]
ments of this Section will have the Notation BARGE k
or PONTOON affixed to the Character of Classifica-
tion. 100
shear stress: τ = [N/mm 2 ]
k

I-0, Section 2, Table 2.9
k = material factor according to Section 2, B.2.
3.2 Barges built for the carriage of special cargo Special attention is to be paid to the transmission of
(e.g. liquid or ore cargo) will have the respective No- lifting forces into the barge structure.
tations affixed to the Characters of Classification (see
also Part 0 – Classification and Surveys, Section 2).
new B.5

new I-0, Section 2, Table 2.9
5. For pontoons carrying lifting equipment,
rams etc. or concentrated heavy deck loads, calcula-
4. General indications tion of the stresses in the longitudinal structures under
such loads may be required. In such cases the stresses
Where barges are intended to operate as linked push given under 4. are not to be exceeded.
barges proper visibility from the tug forward is to be
ensured.
new B.6
Chapter 1 Section 31 F Barges and Pontoons I - Part 1
Page 31–2 GL 2012

C. Watertight Bulkheads and Tank Bulk- phed into the midship structure. A raked fore-end with
heads a flat bottom is to be strengthened according to
Section 6, E.
1. For barges and pontoons, the position of the
new D.3
collision bulkhead is to be determined according to
Section 11, A.2.
4. In pontoons which are not assigned a Nota-
Where in barges and pontoons, the form and construc- tion for restricted service area or which are assigned
tion of their ends is identical so that there is no deter- the Notation RSA (200), the construction of the fore
mined "fore or aft ship", a collision bulkhead is to be peak is to be reinforced against wash of the sea by
fitted at each end. additional longitudinal girders, stringers and web
frames. In case of raked bottoms forward, the rein-

new C.1 forcements are, if necessary, to be arranged beyond
the collision bulkhead. If necessary, both ends are to
2. On barges intended to operate as linked push be reinforced, see also C.1.
barges, depending on the aft ship design, a collision
new D.4
bulkhead may be required to be fitted in the aft ship.
Note
3. A watertight bulkhead is to be fitted at the aft
end of the hold area. In the remaining part of the hull, Also for pontoons sailing only temporarily, for the
watertight bulkheads are to be fitted as required for the purpose of conveyance to another port, within the
purpose of watertight subdivision and for transverse region RSA (200) or beyond that region, the rein-
strength. forcements given in 4. are required

new C.2
covered by D.4

4. The scantlings of watertight bulkheads and of

tank bulkheads are to be determined according to E. Rudder
Sections 11 and 12 respectively.
The rudder stock diameter is to be determined accord-
Where tanks are intended to be emptied by com- ing to Section 14, C.1. The ship's speed speed v0 is not
pressed air, the maximum blowing-out pressure pv to be taken less than 7 knots.
according to Section 4, D.1. is to be inserted in the
formulae for determining the pressures p1 and p2.

new C.3 F. Pushing and Towing Devices, Connecting
Elements
Devices for pushing and towing of linked barges as
D. Structural Details at the Ends well as the connecting elements required for linking
the barges are to be dimensioned for the acting exter-
nal forces.
1. Where barges have typical ship-shape fore
and aft ends, the scantlings of structural elements are The forces are to be specially determined for the re-
to be determined according to Section 8, A.1.2 and spective service range. When determining the scant-
Section 9, A.5. respectively. lings of these devices and elements as well as of the
substructures of the barge hull, the following permis-
The scantlings of fore and aft ends deviating from the sible stresses are to be observed:
normal ship shape are to be determined by applying the
formulae analogously such as to obtain equal strength. – bending and normal stress:

new D.1
100
σ = [N/mm 2 ]
k
2. Where barges are always operating with hori-
zontal trim, in consideration of the forebody form, – shear stress:
relaxations from the requirements concerning strength-
ening of the bottom forward may be admitted. 60
τ = [N/mm 2 ]

new D.2 k

– equivalent stress:
3. Where barges have raked ends with flat bot-
toms, at least one centre girder and one side girder on 120
each side are to be fitted. The girders shall be spaced σv = σ2 + 3τ2 = [N/mm 2 ]
k
not more than 4,5 m apart. The girders shall be scar-
I - Part 1 Section 31 G Barges and Pontoons Chapter 1
GL 2012 Page 31–3

new E 6. In special cases, upon Owner's request, for

unmanned barges and pontoons the number of anchors
may be reduced to one and the length of the chain
cable to 50 % of the length required by Table 18.2.
G. Equipment The notation "special equipment" will be entered into
the Certificate and Register in such cases.
1. Barges and pontoons are to be provided with
anchor equipment, designed for quick and safe opera-
new F.4
tion in all foreseeable service conditions. The anchor
equipment shall consist of anchors, chain cables and
a windlass or other equipment (e.g. cable lifter with 7. If necessary for a special purpose, for barges
a friction band brake, by means of which the anchor and pontoons mentioned under 6., the anchor mass
can be lifted using an auxiliary drum or a crank han- may be further reduced by up to 20 %. Upon Owner's
dle) for dropping and lifting the anchor and holding request the anchor equipment may be dispensed with.
the ship at anchor. The requirements of the GL Rules The notation "Without anchor equipment" will be
for Machinery Installations (I-1-2), Section 14, D. are entered into the Certificate and Register in such cases.
to be observed.
Additionally the notation "For sea voyages anchor

new F.1 equipment is to be available" will be entered into the
Certificate.
2. Unless otherwise specified in this Section, the
required equipment of anchors and chain cables and
new F.5
the recommended ropes 1 for manned barges and pon-
toons are to be determined according to Section 18. A
8. If a wire rope shall be provided instead of a
stream anchor is not required.
chain cable, the following is to be observed:

new F.2

new F.6
3. The equipment numeral Z for determining the
equipment according to Table 18.2, is to be deter- 8.1 The length of the wire rope is to be 1,5 times
mined for pontoons carrying lifting equipment, rams the required chain cable length. The wire rope is to
etc. by the following formula: have the same breaking load as the required chain
cable of grade K1.
Z = D2 3 + B ⋅ f b + f w

new F.6.1
D = displacement of the pontoon [t] at maximum
anticipated draught
8.2 Between anchor and wire rope, a chain cable
fb = distance [m] between pontoon deck and wa- is to be fitted the length of which is 12,5 m or equal to
terline the distance between the anchor in stowed position
and the windlass. The smaller value is to be taken.
fw = wind area of the erections on the pontoon
deck [m2] which are exposed to the wind
new F.6.2
from forward, including houses and cranes in
upright position
8.3 A winch has to be provided which is to be

new F.3 designed in accordance with the requirements for
windlasses (see also the GL Rules for Machinery In-
4. Where more than two anchors are required stallations (I-1-2), Section 14, D.).
the third anchor (spare anchor) may be used as a stern
anchor.
new F.6.3

5. Pontoons having a machinery of sufficient

power which are assigned the Notation RSA (20) or 9. Push barges not operating at the forward or
RSA (50) need not have a spare anchor (3rd anchor). aft end of pushed or towed units need not have any
The power of the machinery will be regarded as suffi- equipment.
cient if it is not less than:

new F.7
N = 0, 08 ⋅ L ⋅ B ⋅ H + 40 [kW]
10. Anchor equipment fitted in addition to that
required herein (e.g. for positioning purposes) is not
part of Classification.
1 See also Section 18, F.
new F.8
I - Part 1 Section 32 B Dredgers Chapter 1
GL 2012 Page 32–1

Section 32

Dredgers

A. General
7. The thickness of main structural members
1. For the purposes of this Section, "dredgers" which are particularly exposed to abrasion by a mix-
means hopper dredgers, barges, hopper barges and ture of spoil and water, e.g. where special loading and
similar vessels which may be self-propelled and non- discharge methods are employed, are to be adequately
self-propelled and which are designed for all common strengthened. Upon approval by GL such members
dredging methods (e.g. bucket dredgers, suction may alternatively be constructed of special abrasion
dredgers, grab dredgers etc.) resistant materials.

new A.2
new B.3
Dredgers intended for unusual dredging methods and
ships of unusual form will be specially considered. 8. On dredgers with closed hopper spaces suitable
structural measures are to be taken in order to prevent

new A.1.1 accumulation of inflammable gas-air mixture in the
hopper vapour space. The requirements of the GL Rules
for Electrical Installations (I-1-3), are to be observed.
2. The requirements given in Sections 1 – 22
apply to dredgers covered by this Section unless oth-
new B.4
erwise mentioned hereinafter.

new A.1.1
B. Documents for Approval
3. Dredgers built in accordance with the re-
quirements of this Section, will have the Notation To ensure conformity with the Rules, the following
DREDGER or HOPPER BARGE, affixed to the drawings and documents are to be submitted in tripli-
Character of Classification. cate in addition to those stipulated in Section 1, G.

I-0, Section 2, Table 2.9
I-0, Section 2, D.2

4. Dredgers engaged in international service are 1. General arrangement plan, showing also the
to comply with the requirements of the ICLL. arrangement of the dredging equipment.

new A.1.2
I-0, Section 2, D.2

2. Longitudinal and transverse hopper bulk-

5. Dredgers with a restricted service area oper- heads, with information regarding density of the spoil
ating exclusively in national waters shall comply, as
and height of overflow.
far as possible, with the requirements of the ICLL.
The height of companionway coamings above deck is
I-0, Section 2, D.2
not to be less than 300 mm.

new A.1.3 3. Arrangement and scantlings of substructures
attached to or integrated into main structural members,
such as gantries, gallows etc. or their seats, seats of
Note dredging machinery and pumps, hopper doors and
For dredgers with a restricted service area as per their gear with seats, positioning equipment and other
Section 1, B.1. operating exclusively in national wa- dredging equipment and devices and their seats.
ters, a special "Dredger Freeboard" is assigned by
I-0, Section 2, D.2
some Administrations.

new A.1.3 Note 4. Longitudinal strength calculations of the most
unfavourable loading conditions for ships of 100 m in
length and more. Calculations with respect to torsion
6. Dredgers intended to work in conjunction
may be required.
with other vessels are to be fitted with strong fenders.

new C.1

new K.4
Chapter 1 Section 32 F Dredgers I - Part 1
Page 32–2 GL 2012

For ships of less than 100 m in length of unusual de-
new D.1
sign and with unusual load distribution, longitudinal
strength calculations may be required. 2. Where hopper doors are fitted on the vessel's

new C.2 centreline or where there is a centreline well for
dredging gear (bucket ladder, suction tube etc.), a
plate strake is to be fitted on each side of the well or
door opening the width of which is not less than 50 %
C. Principal Dimensions of the rule width of the flat keel and the thickness not
less than that of the rule flat keel.
1. Local structures and deviations from the The same applies where the centreline box keel is
principal design dimensions associated with the at- located above the base line at such a distance that it
tachment of the dredging gear, are to be ignored when cannot serve as a docking keel.
determining the principal dimensions in accordance
with Section 1, H. In this case, the bottom plating of the box keel need
not be thicker than the rule bottom shell plating.

new B.1

new D.2
2. Where a "Dredger Freeboard" is assigned in
accordance with A.5., the length L, draught T and 3. On non-self-propelled dredgers and on self-
block coefficient CB as per Section 1, H.4. are to be propelled dredgers with the restricted service area
determined for this freeboard. Notation RSA (50) or RSA (SW) affixed to their
Character of Classification, strengthening of the bot-

new B.2 tom forward in accordance with Section 6, E. is not
required.

4. The flat bottom plating of raked ends which

D. Longitudinal Strength
deviate from common ship forms, is to have a thick-
ness not less than that of the rule bottom shell plating
1. For dredgers, the longitudinal strength re- within 0,4 L amidships, up to 500 mm above the
quirements as per Section 5 apply in general. maximum load waterline. The shell plating above that
For dredgers classed for particular service areas, dis- is to have a thickness not less than the rule side shell
pensations may be approved. plating.

new C.1 The reinforcements required in 1. are also to be ob-

served.
2. For hopper dredgers and hopper barges of
new D.3
less than 100 m in length, longitudinal strength calcu-
lations may be required in special instances. 5. The corners of hopper door openings and of

new C.2 dredging gear wells generally are to comply with
Section 7, A.3. The design of structural details and
3. When calculating the midship section moduli welded connections in this area is to be carried out
in accordance with Section 5, C.4., the net cross sec- with particular care.
tional area of all continuous longitudinal strength
new D.4
members of a longitudinal through box keel fitted
between the port and starboard side hopper doors may
be taken into account.
F. Deck
4. At the ends of the hopper, the longitudinal
strength members are to be carefully scarphed into the
adjacent compartments (see also H.1.3). 1. The deck thickness is to be determined in
accordance with Section 7.
On vessels of less than 100 m in length, the rule deck
plating is to be fitted at least in the following areas:
E. Shell Plating Above engine and boiler rooms, in way of engine and
boiler casings, adjacent to all deck openings exceeding
1. The thickness of the bottom shell plating of 0,4 B in breadth and in way of the supporting structure
dredgers intended or expected to operate while for dredging gear, dredging machinery and bucket
aground, is to be increased by 20 % above the value ladders, etc.
required in Section 6. Where wood sheathing is fitted, the deck plating
thickness required in Section 7, A.7. is sufficient un-
I - Part 1 Section 32 G Dredgers Chapter 1
GL 2012 Page 32–3

less greater thicknesses are required on account of 2. Single bottom longitudinally framed
strength calculations.
2.1 The spacing of bottom transverses generally
is not to exceed 3,6 m. Section modulus and web cross
2. At the ends of the hopper space continuity of
sectional area are not to be less than:
strength is to be maintained by fitting strengthened
corner plates. The corners are to be carried out in
W = k ⋅ c ⋅ e ⋅ ℓ2 ⋅ p [cm3 ]
accordance with the requirements of Section 7, A.3.
AW = k ⋅ 0, 061 ⋅ e ⋅ ℓ ⋅ p [cm 2 ]

G. Bottom Structure k = material factor according to Section 2, B.2.

c = 0,9 − 0, 002 L for L ≤ 100 m
1. Single bottom transversely framed
= 0, 7 for L > 100 m

1.1 Abreast of hoppers and centreline dredging e = spacing of bottom transverses between each
wells, the floors are to be dimensioned in accordance other or from bulkheads [m]
with Section 8, A.1.2.1 where ℓmin may be taken as
0,4 B. The depth of floor is not to be less than ℓ = unsupported span [m], any longitudinal gird-
ers not considered
h = 45 ⋅ B − 45 [mm]
p = load pB or p1 as per Section 4, B.3. or D.1.;
h min = 180 mm the greater value to be taken.
The web depth is not to be less than the depth of floors

new E.1.1 according to 1.1.

new E.2.1
1.2 Floors, longitudinal girders etc. below dredg-
ing machinery and pump seats are to be adequately
2.2 The bottom longitudinals are to be deter-
designed for the additional loads.
mined in accordance with Section 9, B.

new E.1.2
new E.2.2

1.3 Where floors are additionally stressed by the 2.3 Where the centreline box keel cannot serve
reactions of the pressure required for closing the hop- as a docking keel, brackets are to be fitted on either
per doors, their section modulus and their depth are to side of the centre girder or at the longitudinal bulk-
be increased accordingly. heads of dredging wells and of hopper spaces. The
brackets are to extend to the adjacent longitudinals

new E.1.3 and longitudinal stiffeners. Where the spacing of bot-
tom transverses is less than 2,5 m, one bracket is to be
1.4 Where the unsupported span of floors ex- fitted, for greater spacings, two brackets are to be
ceeds 3 m, one side girder in accordance with Section fitted.
8, A.2.2.2 is to be fitted. The thickness of the brackets is at least to be equal
to the web thickness of the adjacent bottom trans-

new E.1.4 verses. The brackets are to be flanged or fitted with
face bars.
1.5 Floors in line with the hopper lower cross

new E.2.3
members fitted between hopper doors are to be con-
nected with the hopper side wall by brackets of
approx. equal legs. The brackets are to be flanged or 2.4 Where longitudinal bulkheads and the side
fitted with face bars and are to extend to the upper shell are framed transversely, the brackets as per 2.3
edge of the cross members. are to be fitted at every frame and are to extend to the
bilge.

new E.1.5
new E.2.4

1.6 Floors of dredgers intended or expected to 2.5 The bottom transverses are to be stiffened by
operate while aground are to be stiffened by vertical means of flat bar stiffeners at every longitudinal.
buckling stiffeners the spacing of which is such as to
The depth shall approximately be equal to the depth of
guarantee that the reference degree of slenderness λ for the bottom longitudinals, however, it need not exceed
the plate field is less than 1,0. For λ see Section 3, F.1. 150 mm.

new E.1.6
new E.2.5
Chapter 1 Section 32 H Dredgers I - Part 1
Page 32–4 GL 2012

2.6 The bottom structure of dredgers intended or p = 10 ⋅ ρ ⋅ h (1 + a v ) [kN/m 2 ]

expected to operate while aground is to be dimen-
sioned as follows: h = distance of lower edge of plating or of the

new E.2.6 load centre of the respective member to the
upper edge of overflow [m]
2.6.1 The spacing of the bottom transverses as per av = see Section 4, C.1.1
2.1 is not to exceed 1,8 m. The webs are to be stiff-
ened as per 1.6. ρ = density of the spoil [t/m3]

new E.2.6.1 ρmin = 1,2 t/m3
2.6.2 The section modulus of the bottom longitudi- tK = corrosion addition according to Section 3, K.
nals as per 2.2 is to be increased by 50 %.

new F.1.1

new E.2.6.2
1.2 Stiffeners
2.7 The requirements of 1.2, 1.3, 1.4 and 1.5 are
to be applied analogously. 1.2.1 transverse stiffeners of longitudinal bulk-

new E.2.7 heads and stiffeners of transverse bulkheads:

3. Double bottom Wy = k ⋅ 0, 6 ⋅ a ⋅ ℓ 2 ⋅ p [cm3 ]

3.1 Double bottoms need not be fitted adjacent to
new F.1.2

the hopper spaces.
1.2.2 longitudinal stiffeners:

new E.3.1
Wx = Wℓ
3.2 In addition to the requirements of Section 8,
B.6., plate floors are to be fitted in way of hopper Wℓ = see Section 9, B.3.
spaces intended to be unloaded by means of grabs.

new E.3.2 but not less than Wy

new F.1.2
3.3 Where brackets are fitted in accordance with
Section 8, B.7.4, the requirements as per 2.3 and 2.4 1.3 The strength is not to be less than that of the
are to be observed where applicable. ship's sides. Particular attention is to be paid to ade-

new E.3.3 quate scarphing at the ends of longitudinal bulkheads
of hopper spaces and wells.
3.4 The bottom structure of dredgers intended or The top and bottom strakes of the longitudinal bulk-
expected to operate while aground is to be strength- heads are to be extended through the end bulkheads,
ened in accordance with Section 8, B.1.7. Where ap- or else scarphing brackets are to be fitted in line with
plicable, 2.6 is to be applied analogously. the walls in conjunction with strengthenings at deck

new E.3.4 and bottom.
Where the length of wells does not exceed 0,1 L and
where the wells and/or ends of hopper spaces are
located beyond 0,6 L amidships, special scarphing is,
H. Hopper and Well Construction in general, not required.

new F.1.3
1. The scantlings of the boundaries of hopper
spaces and wells are to be determined as follows:
2. In hoppers fitted with hopper doors, trans-

new F.1 verse girders are to be fitted between the doors the
spacing of which shall normally not exceed 3,6 m.
1.1 Plating

new F.2
t = 1, 21 ⋅ a p ⋅ k + tK [mm]
3. The depth of the transverse girders spaced in
tmin = as per Section 24, A.14 accordance with 2. shall not be less than 2,5 times the
k = see G.2.1 depth of floors as per Section 8, A.1.2.1. The web
plate thickness is not to be less than the thickness of
a, aℓ = spacing of stiffeners [m] the side shell plating. The top and bottom edges of the
transverse girders are to be fitted with face plates. The
I - Part 1 Section 32 K Dredgers Chapter 1
GL 2012 Page 32–5

thickness of the face plates is to be at least 50 % 1.1.1 Bottom plating

greater than the rules web thickness.
– Where the box keel can serve as a docking keel,
Where the transverse girders are constructed as water- the requirements for flat plate keels as per
tight box girders, the scantlings are not to be less than Section 6, B.5. apply.
required in accordance with 1. At the upper edge, a – Where the box keel cannot serve as a docking
plate strengthened by at least 50 % is to be fitted. keel (see also E.2.), the requirements for bottom

new F.3 plating as per Section 6, B.1. – B.3. apply.

new G.1.1.1
4. Vertical stiffeners spaced not more than
1.1.2 Remaining plating
900 mm apart are to be fitted at the transverse girders.
– Outside the hopper space, the requirements for

new F.4 bottom plating as per Section 6, B.1. – B.3. ap-
ply.
5. The transverse bulkheads at the ends of the – Within the hopper space the requirements for
hoppers are to extend from board to board. hopper space plating as per H.1.1 apply. The
thickness of the upper portion particularly sub-

new F.5
jected to damage is to be increased by not less
than 50 %.
6. Regardless of whether the longitudinal or the

new G.1.1.2
transverse framing system is adopted, web frames in
accordance with Section 12, B.3. are to be fitted in
line with the transverse girders as per 2. 1.2 Floors
The requirements as per G.1. and G.2. respectively
The density of the spoil is to be considered when de- apply.
termining the scantlings.

new G.1.2

new F.6
1.3 Stiffeners
7. Strong beams are to be fitted transversely at The requirements for hopper stiffeners as per H.1.2.
deck level in line with the web frames as per 6. The apply.
scantlings are to be determined, for the actual loads

new G.1.3
complying with an equivalent stress of σv = 150/k
[N/mm2]. The maximum reactions of hydraulically
operated rams for hopper door operation are, for in- 2. Strong webs of plate floors are to be fitted
stance, to be taken as actual load. within the box keel in line with the web frames as per
H.6. to ensure continuity of strength across the vessel.
The strong beams are to be supported by means of
new G.2
pillars as per Section 10, C. at the box keel, if fitted.

new F.7 3. With regard to adequate scarphing at the ends
of a box keel, H.1.3 is to be observed.
8. On bucket dredgers, the ladder wells are to be
new G.3
isolated by transverse and longitudinal cofferdams at
the bottom, of such size as to prevent the adjacent
compartments from being flooded in case of any dam-
age to the shell by dredging equipment and dredged K. Stern Frame and Rudder
objects. The cofferdams are to be accessible.

new F.8 1. Where dredgers with stern wells for bucket
ladders and suction tubes are fitted with two rudders,
the stern frame scantlings are to be determined in
accordance with Section 13, C.1.
J. Box Keel
new H.1

1. The scantlings are to be determined as fol-

2. Where dredgers are fitted with auxiliary pro-
lows:
pulsion and their speed does not exceed 5 kn at maxi-

new G.1 mum draught, the value v0 = 7 kn is to be taken for
determining the rudder stock diameter.
1.1 Plating
Chapter 1 Section 32 M Dredgers I - Part 1
Page 32–6 GL 2012

new H.2 M 'y ⋅ e'z M 'z ⋅ e'y

σ = +
I'y I'z

L. Bulwark, Overflow Arrangements My', Mz' = bending moment related to the inertia axis
y'-y' and z'-z' respectively
1. Bulwarks are not to be fitted in way of hop- Iy', Iz' = moments of inertia of the cross section
pers where the hopper weirs discharge onto the deck shown in Fig. 32.1 related to the respec-
instead of into enclosed overflow trunks. Even where tive inertia axis
overflow trunks are provided, it is recommended not
to fit bulwarks. ey', ez' = the greater distance from the neutral axis
y'-y' and z'-z' respectively
Where, however, bulwarks are fitted, freeing ports are
to be provided throughout their length which should The still water bending moments are to be determined
be of sufficient width to permit undisturbed overboard for the most unfavourable distribution of cargo and
discharge of any spoil spilling out of the hopper in the consumables. The vertical still water and wave bend-
event of rolling. ing moments are to be determined in accordance with
Section 5, A. and B.

new I.1
The horizontal still water bending moment within the
2. Dredgers without restricted service range hold length is to be calculated on the basis of the hori-
notation are to be fitted with overflow trunks on either zontal pressure difference between external hydro-
side suitably arranged and of sufficient size to permit static pressure and cargo pressure in still water.
safe overboard discharge of excess water during The following portion of the dynamic moment is to be
dredging operations. added to the horizontal still water moment:
The construction is to be such as not to require cut-
outs at the upper edge of the sheer strake. Where over- ℓ2  (10 T − p0 )2 
flow trunks are carried through the wing compart- Mz = 10 T2 − ⋅ T
24  10 T + p0 
ments, they are to be arranged such as to pierce the
sheer strake at an adequate distance from the deck.
p0 = see Section 4, A.2, with f = 1

new I.2
ℓ = spacing between hinges [m]
3. Dredgers with restricted service area notation
may have overflow arrangements which permit dis- The stresses are not to exceed the following values:
charge of excess water during dredging operations
onto the deck. in still water:

new I.3 L 150

σsw = 15 , max . N/mm 2
k k

in the seaway:
M. Self-Unloading Barges
175
σp = N/mm 2
1. Self-unloading barges covered by this Sub- k
Section are split hopper barges the port and starboard
portions of which are hinged at the hopper end bulk- GL may approve reduced vertical wave bending mo-
heads to facilitate rotation around the longitudinal axis ments if the vessel is intended for dumping within
when the bottom is to be opened. specified service ranges or in sheltered waters only.

new A.2
new J.1

2. Longitudinal strength calculations are to be 3. The bearing seating and all other members of
carried out for self-unloading barges, irrespective of the hinge are to be so designed as not to exceed the
their length, for the unloading condition. following permissible stress values:

new C.3 90
σb = [N/mm 2 ]
k
The bending moments and the stresses related to the
inertia axis y'-y' and z'-z' are to be determined accord- 55
τ = [N/mm 2 ]
ing to the following formula: k
I - Part 1 Section 32 N Dredgers Chapter 1
GL 2012 Page 32–7

N. Equipment
The loads indicated in Fig. 32.1 are to be applied cor-
respond-
ingly. 1. The equipment of anchors, chain cables,
wires and recommended ropes for dredgers for unre-
z' stricted service area having normal ship shape of the
underwater part of the hull is to be determined in ac-
cordance with Section 18. When calculating the
y' Equipment Number according to Section 18, B. bucket
ladders and gallows need not to be included. For
h dredgers of unusual design of the underwater part of
the hull, the determination of the equipment requires
T special consideration.
y' P'L
P'S The equipment for dredgers for restricted service area
is to be determined as for vessels with the Notations
P'B RSA (20) and/or RSA (50).
z'
new K.1

P'S and p'B = water pressure in [kN/m2] 2. For dredgers with the Notation RSA (SW),
at the draught T see Section 30, E.

new K.1
p'L = cargo pressure in [kN/m2]
as per the following formula:
3. The equipment of non-self-propelled dredg-
ers is to be determined as for barges, in accordance
p'L = 10 ⋅ ρ ⋅ h [kN/m2] with Section 31, G.

new K.2
ρ and h see H.1.1

4. Considering rapid wear and tear, it is recom-

Fig. 32.1 Static loads on a self-unloading barge, mended to strengthen the anchor chain cables which
loaded are also employed for positioning of the vessel during
dredging operations.

new J.2
new K.3
I - Part 1 Section 33 B Strengthening against Collisions Chapter 1
GL 2012 Page 33–1

Section 33

Strengthening against Collisions

in this Section are no changes in numbering

3. The definition of the critical situation is en-
tered into the Certificate.
For general cargo ships and tankers, the notation
COLL with a corresponding restrictive note in the
A. General
Certificate may also be granted for individual com-
partments only.
1. Ships, the side structures of which are spe-
cially strengthened in order to resist collision impacts, 4. If wing tanks are arranged in the area to be
may be assigned the Notations COLL, with index investigated which are to be assumed as being flooded
numbers 1 – 6, e.g. COLL2, affixed to the Character whereas the longitudinal bulkheads remain intact,
of Classification. sufficient floatability and stability in such damaged
The index numbers 1 to 6 result from the ratio of the conditions is to be proved. Longitudinal bulkheads
critical deformation energies calculated for both the fitted outside the envelope curve of the penetration
strengthened side structure and the single hulled ship depths determined for the collision cases as defined in
without any strengthening and without any ice B.5. are to be considered intact.
strengthening. The critical deformation energy is de-
fined as that amount of energy when exceeded in case 5. A COLL-notation will be assigned under the
of a collision, a critical situation is expected to occur. provision that the ship has a sufficient residual longi-
tudinal strength in the damaged condition.
The index numbers will be assigned according to
Table 33.1 on the basis of the characteristic ratio C* of
the critical deformation energies as defined in B.8.
B. Calculation of the Deformation Energy
In special cases COLL-notations higher than COLL6
may be assigned if justified by the design and con- 1. The deformation energy has to be calculated
struction of the ship. by procedures 1 recognized by GL.
In case of high-energy-collisions the Minorsky
Table 33.1 COLL-Notation method may be accepted, if the bow and side struc-
tures are found suitable.
C* COLL-Notation
2 COLL1 2. For low-energy-collisions, the Minorsky
method does not give sufficiently precise results.
3 COLL2 Analyses of these collisions are to be based on as-
4 COLL3 sumptions which take into account the ultimate loads
of the bow and side structures hitting each other in the
6 COLL4
area calculated, and their interactions.
10 COLL5
The computations of ultimate loads are to be based on
20 COLL6 the assumption of an ideal elastic plastic material
behaviour. The calculated limit stress RUC to be as-
sumed is the mean value of the yield strength and the
2. Critical situations are, for instance:
tensile strength, as follows:
– tearing up of cargo tanks with subsequent leak-
age of, e.g., oil, chemicals, etc. 1
R UC = ( R eH + R m )
2
– water ingress into dry cargo holds during car-
riage of particularly valuable or dangerous cargo The elongation at fracture of the shell is to be taken as
5 %.
– tearing up of fuel oil tanks with subsequent
leakage of fuel oil
The critical speed vcr is defined as being the speed of
the striking ship; if this speed is exceeded, a critical
situation may be expected. 1 On request, these computations are carried out by GL.
Chapter 1 Section 33 B Strengthening against Collisions I - Part 1
Page 33–2 GL 2012

3. Ships of approximately equal displacement Collision case 4:

and with design draughts approximately identical to
that of the struck ship to be examined are to be as- 3 T2 min + T2 max
sumed as striking ships. ∆T4 = − T1max
4
2 bow shapes are to be investigated:
T1max = design draught of the striking ship
– bow shape 1: raked bow contour without bow
bulb T1min = ballast draught of the striking ship
– bow shape 2: raked bow contour with bow T2max, T2min = analogous draughts of the struck
bulb ship
Extremely fully shaped bow configurations are not to
be used for the computations. 6. Based on the deformation energies calculated
for the strengthened and non-strengthened side struc-
4. The computations are to be carried out for a ture for the different collision cases defined in 5.
rectangular, central impact, making the following above, the mean values of the critical deformation
assumptions: energies are to be evaluated by means of weighting
factors.
– the bow of the striking ship encounters the side
of the struck ship vertically
7. The mean critical deformation energies are to
– the struck ship is floating freely and has no
be calculated for the collision cases 1 to 4 and for both
speed
bow shapes, in accordance with the following formu-
lae:
5. Various collision cases are to be investigated
for bow shapes 1 and 2, for the strengthened and non- for bow shape 1:
strengthened side structure, covering the design and
ballast draughts of the ships involved in the collision. 1
E 01 =  E 01, 1 + 3 E01, 2 + 3 E 01, 3 + E 01, 4 
The essential factor for determining the deformation 8  

energy are the draught differentials ∆T of the ships 1

E11 =  E11, 1 + 3 E11, 2 + 3 E11, 3 + E11, 4 
involved in the collision, see Fig. 33.1. 8  
The following draught differentials are to be considered:
for bow shape 2:
Collision case 1:
1
E 02 =  E 02,1 + 3 E 02, 2 + 3 E 02, 3 + E 02, 4 
∆T1 = T2 max −
3 T1min + T1max 8  
4
1
E 22 =  E 22, 1 + 3 E 22, 2 + 3 E 22, 3 + E 22, 4 
Collision case 2: 8  
T1min + 3 T1max
∆T2 = T2 max − where:
4
Collision case 3: E01, i = deformation energy for the un-
strengthened ship, bow shape 1, col-
T2 min + 3 T2 max lision case i, i = 1 ÷ 4
∆T3 = − T1max
4
E11, i = deformation energy for the strength-
ened ship, bow shape 1, collision
case i, i = 1 ÷ 4

E02, i and E22, i are the respective values for bow

shape 2

8. The ratios of the mean critical deformation

T1
energies are to be calculated by the following formulae:
T2

DT for bow shape 1:

E11
Fig. 33.1 Draught differential ∆T of ships in- C1 =
volved in a collision E 01
I - Part 1 Section 33 C Strengthening against Collisions Chapter 1
GL 2012 Page 33–3

for bow shape 2: Collision case 4:

E 22 T1 = T1max
C2 =
E 02
T2 max + 3 T2 min
T2 =
The characteristic ratio for the ship is the mean value 4
resulting from the two weighted ratios C1 and C2 in
accordance with the following formula: 3. For the assignment of a COLL-notation, in
addition to the characteristic ratio C* according to A.1.
1 (Table 33.1), the minimum values for the mean critical
C* =
2
(
C1 + C2 )
speed v*cr as given in Table 33.2 have to be met.

9. The index defined in A.1. will be fixed on the

basis of the characteristic ratio C* and the correspond- Table 33.2 Minimum values for the mean critical
ing minimum value for the critical speed speed v*cr
v*cr min according to C.3.
COLL-Notation v*cr min [kn]

COLL1 1,0
C. Computation of the Critical Speed
COLL2 1,5
1. The critical collision speed is to be deter- COLL3 2,5
mined by the following formula: COLL4 4,0

E cr  COLL5 5,5
m2 
vcr = 2, 75 1 +  [kn] COLL6 7,0
m2  m1 
v*cr see also 4.
Ecr = deformation energy [kJ], once the critical
speed has been reached
m1 = mass of the striking ship [t], incl. 10 % hy- 4. The mean critical speed vcr results from the
drodynamical added mass weighted critical speeds of collision conditions 1 ÷ 4
m2 = mass of the struck ship [t], incl. 40 % hydro- for both bow shapes, in accordance with the following
dynamical added mass formulae:

2. When calculating the critical speeds for the for bow shape 1:
collision cases in accordance with B.5., the following
draughts are to be assumed: 1
vcr1 = [ v1cr1 + 3 v1cr2 + 3 v1cr3 + v1cr4 ]
8
Collision case 1:
v1cri = critical speed for bow shape 1, collision case
3 T1min + T1max
T1 = i, i = 1 ÷ 4
4
T2 = T2 max for bow shape 2:

1
Collision case 2: vcr2 = [ v2cr1 + 3 v2cr2 + 3 v 2cr3 + v2cr4 ]
8
T1min + 3 T1max
T1 = v2cri = critical speed for bow shape 2, collision case
4
i, i = 1 ÷ 4
T2 = T2 max
The critical speed characteristic for the ship results as
Collision case 3: mean value from the two weighted speeds vcr1 and

T1 = T1max vcr2 , in accordance with the following formula:

3 T2 max + T2 min 1
T2 = v*cr = ( vcr1 + vcr2 ) [kn]
4 2
I - Part 1 Section 34 C Special Requirements for In-Water Surveys Chapter 1
GL 2012 Page 34–1

Section 34

Special Requirements for In-Water Surveys

A. General ance of at least 200 mm under consideration of acces-

sibility of measuring points.
Ships intended to be assigned the Class Notation IW (In-
Water Survey) shall comply with the requirements of
new B.4
this Section enabling them to undergo in-water surveys.
5. It shall be possible to present proof of tight-

new A.1
ness of the stern tube, in case of oil lubrication, by
static pressure loading.

new B.5
B. Special Arrangements for In-Water 6. Liners of rudder stocks and pintles as well as
Surveys bushes in rudders are to be marked such that the diver
will notice any shifting or turning.
1. The ship's underwater body is to be protected
new B.6
against corrosion by an appropriate corrosion protec-
tion system which consists of a coating system in
7. For other equipment, such as bow thrusters
combination with cathodic protection.
the requirements will be specially considered taking
The coating system without antifouling shall have a into account their design.
minimum dry film thickness of 250 µm, shall be com-
new B.7
patible with the cathodic protection and shall be ap-
propriate for mechanical underwater cleaning. The
cathodic protection system has to be designed for at 8. In case of existing ships below 100 m in
least one docking period. length the requirements specified in paragraphs 3., 4.
and 6. may be dispensed with.

new B.1

new B.8
2. The ship's underwater body is to be provided
with fixed markings and unmistakable inscriptions
such as to enable the diver to determine his respective C. Documents and for Approval, Trials
position. For this purpose the corners of tanks in the
cargo hold area, and the location of the centre line and 1. In addition to the approval documents listed
transverse bulkheads every 3 – 4 m, are to be marked. in Section 1, G. drawings and, where necessary in-

new B.2 struction manuals, documenting the arrangements
specified in B. are to be submitted.
3. Sea chests shall be capable of being cleaned
LoD
under water, where necessary. To this effect the clo-
sures of the strainers are to be designed such that they 2. Prior to commissioning of the vessel the
may be opened and closed in an operationally safe equipment is to be surveyed and subjected to trials in
manner by the diver. In general the clearance of access accordance with the Surveyor's.
openings should not be less than 900 × 600 mm.

new C.1

new B.3
3. A remark in the IW Manual should be im-
4. Clearances of the rudder and shaft bearings plemented that the diver or repair company have to
shall be capable of being measured with the ship afloat provide relevant tools to grant a safe working condi-
in every trim condition. If within the scope of sched- tion on the vessel similar to docking condition.
uled periodical surveys drydockings are to be per-
new C.2
formed at intervals of 2,5 years or less, the installation
of special underwater measuring equipment may be
dispensed with. Inspection ports are to have a clear-
I - Part 1 Section 34 C Special Requirements for In-Water Surveys Chapter 1
GL 2012 Page 34–2

– instructions regarding measures to be taken by

4. For facilitating the performance of surveys, the crew for ensuring risk-free diving operations
detailed instructions are to be kept aboard as guidance – description of measuring method for determina-
for the diver. These instructions should include details, tion of rudder and shaft clearances
such as:
– additional instructions, where required, depend-
– complete colour photograph documentation of ing on structural characteristics
all essential details of the underwater body,
starting from the newbuilding condition – coating specification, cathodic protection, see
Section 35, H.2.
– plan of the underwater body showing the loca-
tion and kind of inscriptions applied
new C.3
I - Part 1 Section 35 C Corrosion Protection Chapter 1
GL 2012 Page 35–1

Section 35

Corrosion Protection

in this Section are no changes in numbering 1.3 The coating shall be of good resistance to with-
A. General Instructions stand the mechanical stresses incurred during the sub-
sequent working of the steel material in the shipbuild-
1. Field of application ing process.

1.1 This section deals with the corrosion protec-

tion measures specified by GL with respect to seago- 1.4 Flame-cutting and welding speed are not to
ing steel ships. Details of the documentation necessary be unduly impaired. It shall be ensured that welding
for setting up the corrosion protection system are laid with all welding processes customary in the building
down herein (planning, execution, supervision). of ships can be conducted without impermissibly
impairing the quality of the weld seam, see the GL
1.2 Corrosion protection for other types of ship Rules for General Requirements, Proof of Qualificati-
as well as other kinds of material, e.g. aluminium, is to ons (II-3-1), Approvals, Section 6.
be agreed separately in consultation with GL.

1.3 Requirements with respect to the contractors 1.5 Due to the possible strain to the system pre-
executing the work and the quality control are subject sented by cathodic protection, seawater and chemicals,
to the conditions laid down in Section 1, N.1.1 and 1.2. only shop primers are to be used which are alkali-fast
and not hydrolyzable.
1.4 Any restrictions which may be in force con-
cerning the applicability of certain corrosion protec-
tion systems for special types of vessels (e.g. tankers 1.6 The suitability and compatibility of shop prim-
and bulk carriers) have to be observed. GL is to be er for use in the corrosion protection system is to be
consulted when clarifying such issues. guaranteed by the manufacturer of the coating materials.

1.5 Supplementary to this Section, the GL Guide-

lines for Corrosion Protection and Coating Systems (VI- 2. Approvals
10-2) contain further comments and recommendations
for the selection of suitable corrosion protection systems, Only those overweldable shop primers may be used
as well as their professional planning and execution1. for which the Society has issued a confirmation of
acceptability based on a porosity test in accordance
with the GL Rules for General Requirements, Proof of
B. Shop Primers Qualifications (II-3-1), Approvals, Section 6.

1. General For the use of shop primers in combination with coat-

ing systems in ballast water tanks the GL Rules for
1.1 Shop primers are used to provide protection for Coating of Ballast Water Tanks (VI-10-1) shall further
the steel parts during storage, transport and work proc- be observed.
esses in the manufacturing company until such time as
further surface preparation is carried out and the subse-
quent coatings for corrosion protection are applied.
C. Hollow Spaces
1.2 Customarily, coatings with a thickness of
15 µm to 20 µm are applied.
Under normal yard conditions, this should provide 1. General
corrosion protection for a period of approx. 6 months.
Hollow spaces, such as those in closed box girders,
tube supports and the like, which can either be shown
to be air tight or are accepted as such from normal
–––––––––––––– shipbuilding experience, need not have their internal
1 In addition, GL also offers advisory services for general ques- surfaces protected. During assembling, however, such
tions concerning corrosion and corrosion protection. hollow spaces have to be kept clean and dry.
Chapter 1 Section 35 H Corrosion Protection I - Part 1
Page 35–2 GL 2012

D. Combination of Materials 1.2 The coating used shall be approved by the

manufacturer for application in cargo holds.
1. General
1.3 The coating manufacturer’s instructions with
1.1 Preventive measures are to be taken to avoid regard to surface preparation as well as application
contact corrosion associated with the combination of conditions and processing shall be adhered to.
dissimilar metals with different potentials in an elec-
trolyte solution, such as seawater.
1.4 The minimum thickness of the coating shall
1.2 In addition to selecting appropriate materials, be 250 µm in the complete area defined under 1.1.
steps such as suitable insulation, an effective coating
and the application of cathodic protection can be taken
in order to prevent contact corrosion. 2. Documentation

2.1 The coating plan is to be submitted for ex-

amination.
E. Fitting-Out and Berthing Periods
A description of the work necessary for setting up a
1. General coating system and the coating materials to be used
shall be contained in the coating plan.
1.1 For protection against corrosion arising from
stray currents, such as those occurring due to inappro- 2.2 A coating report is to be compiled in such a
priate direct-current electrical supply to the ship for way that details of all the work processes executed,
welding or mains lighting, as well as those arising including the surface preparation as well as the coat-
from direct-current supplies to other facilities (e.g. ing materials used, are recorded.
shore cranes) and neighbouring ships, the provision of
(even additional) cathodic protection by means of
sacrificial anodes is not suitable. 2.3 This documentation is to be compiled by the
coating manufacturer and/or the contractor executing
1.2 Steps are to be taken to prevent the formation the work and/or the yard. An inspection plan shall be
of stray currents, and suitable electric drainage is to be agreed to between the parties involved. The papers
provided. pertaining to the documentation shall be signed by
these parties. On completion of the coating system, the
signed papers constituting the documentation are to be
1.3 Particularly in the event of lengthy fitting-out
handed to the surveyor for approval.
periods, welding rectifiers are to be so arranged that
stray currents can be eliminated.

H. Corrosion Protection of the Underwater

F. Corrosion Protection of Ballast Water Hull
Tanks
The GL Rules for Coating of Ballast Water Tanks (VI- 1. General
10-1) are applicable.
1.1 Vessels intended to be assigned the Class
Notation IW (In-Water Survey) shall provide a suit-
G. Corrosion Protection of Cargo Holds able corrosion protection system for the underwater
hull, consisting of coating and cathodic protection.
1. General
1.2 Coatings based on epoxy, polyurethane and
1.1 On bulk carriers, all internal and external polyvinyl chloride are considered suitable.
surfaces of hatch coamings and hatch covers, and all
internal surfaces of the cargo holds, excluding the flat 1.3 The coating manufacturer’s instructions with
tank top areas and the hopper tanks sloping plating regard to surface preparation as well as application
approximately 300 mm below the side shell frame and conditions and processing shall be observed.
brackets, are to have an effective protective coating
(epoxy coating, or equivalent), applied in accordance 1.4 The coating system, without antifouling, shall
with the manufacturer’s recommendation. In the selec-
have a minimum dry film thickness of 250 µm on the
tion of coating due consideration shall be given in
complete surface, shall be compatible to cathodic
consultation with the owner to the intended cargo and
protection in accordance with recognized standards,
conditions expected in service.
and shall be suitable for being cleaned underwater by
mechanical means.
I - Part 1 Section 35 H Corrosion Protection Chapter 1
GL 2012 Page 35–3

– arrangement of the ICCP system

1.5 The cathodic protection can be provided by
– location and constructional integration (e.g. by a
means of sacrificial anodes, or by impressed current
cofferdam) of the anodes in the vessel's shell
systems. Under normal conditions for steel, a protection
current density of at least 10 mA/m2 is to be ensured. – descriptions of how all appendages, e.g. rudder,
propeller and shafts, are incorporated into the
1.6 In the case of impressed current systems, cathodic protection
overprotection due to inadequately low potential is
– electrical supply and electrical distribution system
tobe avoided. A screen (dielectric shield) is to be pro-
vided in the immediate vicinity of the impressed- – design of the dielectric shield
current anodes.
2.3 The work processes involved in setting up the
1.7 Cathodic protection by means of sacrificial coating system as well as the coating materials to be
anodes is to be designed for one dry-docking period. used shall be laid down in the coating plan.

2.4 A coating protocol is to be compiled in such a

1.8 For further instructions refer to the GL Guide-
way that details of all the work processes executed,
lines for Corrosion Protection and Coating Systems
including the surface preparation as well as the coat-
(VI-10-2), Section 7.
ing materials used, are recorded.
1.9 In the case of other materials, such as alumin- 2.5 This documentation is to be compiled by the
ium for instance, special conditions are to be agreed coating manufacturer and/or the contractor executing
with GL. the work and/or the yard. An inspection plan shall be
agreed to between the parties involved. The papers
2. Documentation pertaining to the documentation have to be signed by
these parties. On completion of the coating system, the
2.1 The coating plan and the design data for the signed papers constituting the documentation are to be
cathodic protection are to be submitted for examina- handed to the surveyor for approval.
tion.
2.6 In the case of impressed current systems, the
2.2 In the case of impressed current systems, the functionability of the cathodic corrosion protection is
following details shall also be submitted: to be tested during sea trials. The values obtained for
the protection current and voltage shall be recorded.
I - Part 1 Annex A A Load Line Marks Chapter 1
GL 2012 Page A–1

Annex A

Load Line Marks

sketches on page A-2. Where no other mark is stipu-

in this Section are no changes in numbering
lated by national regulations of the competent Author-
ities, (e.g. in the Federal Republic of Germany SB-
GL) there will be added the letters G–L. The ring,
lines and letters are to be painted white or yellow on a
A. Load Line Marks of GL dark ground or else, black on a light ground. They
shall be permanently attached on both sides of the
On application, GL calculates freeboards in accor- ship.
dance with the Regulations of the ICLL and with any
existing relevant special national regulations, and (The sketch is drawn for the starboard side.)
subsequently issue the necessary Load Line Certifi- With ships having a restricted service range, depend-
cates wherever authorized to do so by the competent ing on the respective range, the seasonal marks, such
Authorities of the individual States. as for Tropical and Winter North Atlantic trade, are
omitted.
Applications for issuance of Load Line Certificates or
for surveys for freeboard admeasurements are to be Ships of more than 100 m in length do not get a WNA
made to either GL Head Office or to a Society's In- mark. For these ships WNA is equal to W, and the
spection Office. Freeboards will then be calculated on LWNA- mark is affixed at the same level as the W-
the basis of the survey reports and admeasurements by mark.
the Head Office.
On German ships, the letter "L" in the timber mark is
Subject to the "Gesetz über die Aufgaben des Bundes replaced by the letter "H".
auf dem Gebiet der Seeschiffahrt", in the Federal
The ICLL entered into force on 21st July, 1968.
Republik of Germany, See-Berufsgenossenschaft and
GL are entrusted with the enforcement of the ICLL. For ships the keels of which were laid prior to 21st
GL carry out on behalf of See-Berufsgenossenschaft July, 1968, the conditions for assignment of the free-
the survey for determining the freeboard, the calcula- board subject to the Load Line Convention 1930 con-
tion and checking of the freeboard and, where neces- tinue to be valid as a part of the ICLL. Where the
sary, periodical surveys. advantages of the ICLL are intended to be utilized,
the respective ships are to comply with all require-
The load lines assigned by GL are marked amidships ments of that Convention as for a new ship.
in accordance with the Load Line Certificate as per
Chapter 1 Annex A A Load Line Marks I - Part 1
Page A–2 GL 2012

Load Line Marking for Seagoing Ships

300 mm

deck line

25 mm
summer freeboard

540 mm forward
assigned

50 mm
35 mm

mm

of ring to top of each line

75 mm

to be taken from centre

25
TF

25 mm

measurements
F
G L T

These
Upper edge S
of horizontal line passing 230 mm
W
115 mm
25 mm

through the centre of ring WNA

25 mm
300 mm
450 mm 25 mm 230 mm

Load Line Marking for Seagoing Ships Carrying Timber Deck Cargoes
25 mm

300 mm

deck line summer freeboard

540 mm aft 540 mm forward

assigned

LTF
to be taken from centre

50 mm
These measurements

LF
mm

of ring to top of each line

75 mm 35 mm
of ring to top of

to be taken from centre

LT
230 mm TF
25

25 mm
each line

measurements

LS
F
G
115 mm

T
These

LW S
230 mm
25 mm

LWNA W
WNA
25 mm
25 mm

300 mm
230 mm 25 mm 450 mm 25 mm 230 mm

Upper edge
of horizontal line passing
through the centre of ring
I - Part 1 Annex B A Ice Class Draught Marking Chapter 1
GL 2012 Page B–1

Annex B

Ice Class Draught Marking

draught mark at the maximum permissible ice class

in this Section are no changes in numbering
draught amidships if the summer load line in fresh water
is located at a higher level than the UIWL. The purpose
of the warning triangle is to provide information on the
A. Ice Class Draught Marking of GL draught limitation of the vessel when it is sailing in ice
for masters of icebreakers and for inspection personnel
According to Section 15, A.2.2, ship's sides are to be pro- in ports.
vided with a warning triangle and with an ice class

300 mm
25 mm
ICE

1000 mm

TF
F
G T
S
W
WNA
540 mm aft

ICE 25 mm
230 mm

Note
3. The dimensions of all lettering are to be the same
1. The ice class draught mark is to be centred 540 as those used in the load line mark (see Annex A).
mm abaft the centre of the load line ring or 540
mm abaft the vertical line of the timber load line 4. The warning triangle, ice class draught mark and
mark, if applicable (the sketch is shown for the lettering are to be cut out of 5 - 8 mm plate and
starboard side). The ice class draught mark is to then welded to the ship's side. They are to be
be 230 mm in length and 25 mm in width. painted in a red or yellow reflecting colour in or-
der to be plainly visible even in ice conditions.
2. The upper edge of the warning triangle is to be
centred above the ice class draught mark, 1000
mm higher than the Summer Load Line in fresh-
water but in no case higher than the deck line.
The sides of the warning triangle are to be 300
mm in length and 25 mm in width.